Japanese Invasion of China: Foreign Relations--The United States

Japanese invasion of China
Figure 1.--

Japan had been a British and American ally in World War I. The Harding Administration after World War I negotiated the Washington Naval Treaties. The goal was to limit naval arms spending, particularly Japanese spending and to get Japanese acceptance of the Open Door principle in China. The Japanese reluctantly agreed, but the Japanese military was outraged at what they considered a national insult. Few Americans outside the Navy saw Japan as a military threat. Most Americans to the extent that they thought on the subject saw the Japanese as a stable, hard working people in contrast to the tumult and poverty of China. The Japanese invasion and the brutality reported by missionaries and journalists powerfully swung American public opinion toward the Chinese, The Japanese attack on the USS Panay also affected American public opinion. The Roosevelt Administration took office 2 years after the Japanese seizure of Manchuria and establishment of the puppet Manchuko state. The Roosevelt administration like the Hoover Administration before it refused to recognize Manchuko and after the invasion of China proper (1937) gradually increased diplomatic pressure on Japan to withdraw from China and eventually began to aid the KMT. American journalists had a powerful impact on American public opinion. And it would be America's constant and increasing support of China that would cause the Jaspanese to finally decided not to strike north and support their Axis ally in the invasion of the Soviet Union, but rather to strike south and bring the United States and its massive industrial power vinto the War.

Japanese 21 Demands on China (1915)

When World War broke out in Europe, President Yuan Shikai was in the process of creating a dictatorship and eventually resestablishing the imperial system with himself as emperor. Japan having fought the First Sino-Japanese War with China (1894-96) and seized Korea (1909) used the instability in China to press major demands. After establishing themselves in the German concession in Shandong (1914), the Japanese presented the Twenty One Demands (二十一個條項, Èr shí yīgè tiáo xiàng) to Yuan's Government. They made extensive demands on China, but in essence would have turned China into an emense Japanese protectorate. Yuan rejected the Japanese demands, but did accept the Japanese demand that China recognize its possession of the former German concession in Shandong. Yuan also accepted Japanese interests in southern Manchuria and eastern Inner Mongolia. Yuan's attempt to become the new emperor eventually resulted in rebellion and provincial military commanders establishing themselves as war lords. Admost the turmoil, Yuan died. The idea of a united China was firmly established in the Chinese mind. The war lords made alliances which were constantly shifting in an effort to seize control of the national government in Beijing. Japan continued to press their demands. The Allies (Britain, France, and Italy, but not the United states) in secret communiques agreed to recognize the Japanese claims in China in exchange for the expanded Japan's naval action against Germany. (The Japanese committed a naval squadron in the Mediterranean.) The Twenty-One Demands would be the subject of extensive negotiations between Japan and China as well as with other countries, especiallt the United states. Japanese Governments would at times press the demands and other times pursue more moderate polivies. But these demabds were a basic statement of what Japanese natiinalists wanted in China and woukd eventually lead to the Second Sino-Japanese War (1937-45). Threatened with war, the corrupt Anfu government signed a humiliating treaty with Japan, acceding to Japan’s demands.

Washington Naval Treaties

Japan had been a British and American ally in World War I. The Harding Administration after World War I negotiated the Washington Naval Treaties. The goal was to limit naval arms spending, particularly Japanese spending and to get Japanese acceptance of the Open Door principle in China. The major naval powers (America, Britain, France, Italy, and Japan) agreed to substantial limitations on their naval strength which at the time was measured in battleships. American Secretary of State, Charles Evans Hughes organized a conference to address the problem of spiraling naval expenditures as a result of the naval arms race. Senator William E. Borah, Republican of Idaho, who had led the fight against American ratification of the Treaty of Versailles and participation in the League of Nations, strongly advocated efforts to limit the arms race. His efforts were not at first favored by the new Harding administration, but was eventually adopted as the Republican alternative to the Democrat's (Wilson's) policy of collective security through the League of Nations. The Conference opened on Armistice Day 1921--a very meaningful date so close to World War I. The American delegation was led by Secretary of State Charles Evans Hughes. Hughes shocked the other delegates by proposing a major reduction in naval fleets and not just limitations on new construction. This was far beyond what the other countries had anticipated. Some have called this one of the most dramatic moments in American diplomatic history. The American proposals entailed scrapping almost 2 million tons of warships as well as a lengthy “holiday” on new building. The consequences of the Washington Treaties went far beyond this.

Japanese Outrage

The Japanese reluctantly agreed, but the Japanese military was outraged at what they considered a national insult. Few Americans outside the Navy saw Japan as a military threat.

American Views

Most Americans to the extent that they thought on the subject saw the Japanese as a stable, hard working people in contrast to the tumult and poverty of China.

London Naval Arms Conference Treaty (1930)

The world naval powers convened in London to discuss continued naval arms limitations. The London Conference was strongly promoted by British Prime Minister Ramsey MacDonald who desired to continue if not increase the limitations established by the Washington Naval Treaties (1921). The Conference was held as the Wall Street Crash (1929)was spiraling into a serious world-wide economic criis and the major powers desired to cut back on gobernment sopending, especially military power. A Treaty was signed (April 1930). The signatories agreed to build no replacements of capial ships before 1937. American, Britain, and Japan agreed to avoid a arms race in destoyers and submarines. They also for the first time placed limits ob cruisers. America and Britain were allocated a cruisr tonnage about one and half that of Japan. The partipants agreed to another naval arms conferemnce in 1935. The inferior status of Japan has caused considerable resentment after the Washington Naval Conference (1921-22). After the London Conference it set in motion political changes of serious consequences.

Manchuria (1931)

The United tates was not a member of the League of Nations and involved in League sanction. The Roosevelt Administration took office 2 years after the Japanese seizure of Manchuria and establishment of the puppet Manchuko state. The Roosevelt administration like the Hoover Administration before it refused to recognize Manchuko. Secretary of State Henry Stimson set U.S. policy by what became known as the 'Stimson Doctrine'. (Stimpson would later become American Secreytary of War.) The Ameican response to the Japnese invasion, however, was only diplomatic. The U.S. threatened no military or economic retaliation.

A New Tool: Economic Sanctions

It would be the United States and not the League of Nations that would eventually confront Japan over its aggresive policy. The principal instruments that the United States would use would be diplomacy and a new diplomatic instrument, economic sanctions. The basis for this was the unsucessful League of Nations efforts. President Lowell of Harvard University and firmer Secretary of War Newton Baker suggested that the United States support any sanctions adopted by the League (1932). Senator Borah, a principal opponent of the League and an ardent isolationist insisted "That way lies madness." The failure the Hoover Administration to support the League was a factor discourging the League from pursuing any effective action. [Williams] It would be the Roosevelt Administration that would adopt the policy of using economic sanctions to disuade Japan from aggression and war.

London Naval Arms Conferece (1935)

The Americans and the British attempted to convene another naval arms conference (1935). The major naval powers met in London for another round of naval talks to renew the existing limitations decided on at the Washington Naval Conference (1921-22) and London Naval Conference (1930). These limits were due to expire (1935-37). The militarsts in Japan were now in virtual control of the Government. The Japanese demanded parity with America and Britain. When this was not granted, the Japanese withdrew from the planned conference. This meant the exisiting limitations would expire. All three nations initiated battleship rebuilding programs with expiration of the treaty in 1936. Japan initiated the largest building program, a massive program to build 150 ships. The Japanese laid down two super battleships, Yamoto and Musashi, but the actual dimensions of these massive ships were kept secret. They were 69,100 tons, twice the size of treaty limitations. Germany built Bismarck and Tirpitz at 52,600 tons. The falure of the Conference created enough concen in Congress to approve an American naval building program, although a smaller program than initiated by the Japanese, only 100 vessels. Even so the new ships would only bring the Navy up Treaty limits. Two aircraft carriers were laid down in 1936 and 1937, each within Treaty limits. (These were USS Wasp (CV-7) and the larger USS Hornet (CV-8). No one knew at the time just how important these carriers would be. Both would reach the fleet in 1941 in time to participate in the critical Pacific battles of 1942. The Rooevelt Administration justified the appropriations in part as they would create jobs. The Isolationists and peace lobby opposed the appropriations with the slogan "Schools, not battleships". New battleships were authorized, but actual keels were not laid until after the war began in Europe. Only the USS North Carolina (BB-55) reached the fleet before Pearl Harbor.

Japanese Invasion of China (1937)

The Japanese invasion and the brutality reported by missionaries and journalists powerfully swung American public opinion toward the Chinese. Reporting on Japanese actions in Manchuria had been very limited. This was not the case in China. From the beginning accounts of Japanese brutality were priominently featured in American newspapers. The Rape of Nanking became known all over the world and of course that was just one city. and after the invasion of China proper gradually increased diplomatic pressure on Japan to withdraw from China and eventually began to aid the KMT. American journalists had a powerful impact on American public opinion. And it would be America's constant and increasing support of China that would cause the Japanese to finally decided not to strike north and support their Axis ally in the invasion of the Soviet Union, but rather to strike south and bring the United States and its massive industrial power vinto the War.

USS Panay (1937)

American involvement in China did not begin with the Japanese invasion and the Roosevelt Administration. American naval vessels began cruises on the Yangtze River in 1854. The mission of these early cruises was to show the flag and support American consular officers. The naval mission grew ever more complex as the authority of the Imperial Government deteriorated in the late 19th century and became an important instrument of American foreign policy. Operations included putting landing parties ashore on occassion to protect U.S. interests. The U.S. Navy after the turn of the 20th century began to conduct the patrols in a more organized fashion. The Navy deployed purpose-built gunboats and began coordinting operations with the Britidsh Royal Navy. The U.S. Navy was also deployed in anti-piracy patrols off the Chinese coast. Japnese forces were moving up the Yangtze River toward the Chinese capital which had been evacuated from Peeking to Nanking. Two U.S. Navy gunboats were at Nanking, the U.S.S. Luzon and the U.S.S. Panay. Chinese officials notified the American Embassy on November 27, 1937 that it must evacuate. The Ambassador and most of the Embasy personnel departed the net day on the U.S.S. Luzon. The rest of the Embassy staff remained another week. Ambassador Grew notified the Japanese government on December 1 that the U.S.S. Panay would be departing. Panay took on Embassy officials and some civilians and began upriver. It escortied three Standard Oil barges. Two Royal Navy gunboats and some other British boats followed. A Japanese artillery position commanded by a Colonel Hashimoto fired on the ships, hoping that it might precipatate a war with America and end civilian influence in the Japanese Government--finalizing the "Showa Restoration." Panay flew an American flag as well as had Americn flags painted on the awnings and topsides. December 12 was a clear, sunny day with perfect visability. At about 1330, three Japanese Navy bombmers attacked Panay followed by 12 more planes that dive-bombed and 9 fighters that strafed. The attack was deliberate lasting over 20 minutes. As Panay began sinking, the Japanese sraffed the lifeboats and river bank. Two sailors and civilian were killed. there were 11 sailors seriously wounded. passenger died of their wounds; eleven officers and men were seriously wounded. [Morrison, pp. 16-18] There was no outcry in America for war. The Japanese Government which had not ordered the attack, promtly appolgized and offered compensation. The attack was, however, coordinated by military officers. Both the American public and the Roosevelt Administration were releaved that war could be overted. [Freidel, pp. 290-291.] The Japanese when they arrived in Nanking proceeded to conduct one of the greatest attrocities in their campaign in China--known to history as the Rape of Nanking". The Panay was also involved in intelligence collection. The Admistration for a while considered economic sanctions against the Japanese. The Navy gunboats missions continued through 1941 until the Japanese attack on Pearl Harbor. The Japanese carfully avoided any further incidents. The Japanese officers responsible, however, got what they so ardently desired nearly 4 years later.

American Neutrality Act (1937)

One action that did not take place after the Japanese invasion was that President Roosevelt did not invoke the embargo provisions of the Neutrality Act. Here the Act seem more appropriate than the Spanish Civil War when the Act was invoked. The Japanese invasion began a major war between two countries, although neither country actually declared war. Unlike with Spain, there was not great cry among America's powerful isolationist lobby to invole the Act. The reason for this is unclear and an assessment would require a major study. Our belief is that it probably reflects the much greater fear of war with Germany and much less concern over the dangers posed by Japan. (The Isolationist Movement included those with a wide range of interests and motives, but fear of war with Germany was a major factor.) An corrilary reason is that most Americans, in part because of prevalent rascist attitudes, did not see Japan as a serious military threat. The Panay incident (December 1937) had in addition affected American public opinion. The Administration's failure to act also probably reflects the learning experience after the enbargo on Spain and a judgement that in this case an embargo would hurt China much more than Japan. The President and the American people favored China in the crisis, and by not invoking the 1936, the President left open China's ability to obtin supplies in America.

American Moral Embargoes (1938)

The first signifucant American response to Japanese aggression was informal executive pressure on U.S. exporters, what the Roosevelt Administratuioin called a 'moral embargo', expressing America's moral outrage at Japanese atrocu=ities in China. [U.S. State Department, 1943] The initial American reaction was conducted at the Japanese bombing of civilians in China whuch the Japanese escalated when they failed to force the Nationalist Government to capitulate. Secretary of State Cordell Hull condemned the slaughter and its 'material encouragement' (June 1938). The first actual action occurred a month later, the State Department notified American aircraft manufacturers and exporters that the U.S. Government was 'strongly opposed' to the sale of airplanes and related materiel to those nations using airplanes to attack civilian populations (July 1938). Thus was essentially a non-binding embargo. The U.S. Government extended this non-binding embargo was extended to airplane manufacture and to plans, plants, and technical information for the production of high-quality aviation gasoline. These measures resulted in the suspension of the export to Japan of aircraft, aeronautical equipment, and other materials within the scope of the moral embargoes. As Japanese purchases of items other than aircraft and aeronautical equipment were minuscule, the moral embargo ultimately stopped the exportation of arms to Japan.

Finncial Dealings

From the very beginning, the Roosevelt Administration was aware that Section 5(b) of the Trading with the Enemy Act of 1917 which gave the the president the authority to regulate American financial dealings with all foreign countries and entities, President Roosevelt apparently gave some thought to a financial freeze after Japan invaded China (July 1937). The Administration, however, continued to rely on moral embargos and statements. U.S. financial experts were reportedly convinced that Japan could conduct a lengthy war because of its lack of hard currency. Unknown at the time was that the Japanese banks with Government support had hidden a substntial reserve of dollars and other hard currency so it could stave off bankruptcy perhaps as long as 1943. [Miller]

American Aid to China: War Loans (1939)

The Japanese invasion of China did not go as planned. The Chimese resisted, and the Japanese while conquering large areas of the country were unable to force a conclusion to the War. And Japanese aggression caused both concern within the American Governmrnt and great sympathy among the public. Here American missionaries were a major factor in shaping public opinion. Isolationist sentiment against involvenent was not as stong as against involbvement in Europe. The U.S. Government approved a $25 million loan (1939). President Roosevekt by not invoking the Neurtlity cts had left open China's bility to buy war material in America. Now the President was going to help finance these purchases. This allowed the beleagered Chinese Nationalists to buy American planes for the Chinese Air Force. Since the invasion of China in 1937, the Japanese had been using terror bombings of unprotected Chinese cities as a major part of their war effort. Of course 25 million in 1939 dollars was much more than current dollars, but still in terms of China's needs was not aassive sum. But it was just the money, but the commitment America was making to suppott China and oppose Japanese aggression. America wa the only country in 1939 that could make this sort of commitment.

Termination of Trade Treaty (July 1939)

The United States and Japan had signed the Treaty of Commerce and Navigation with Japan during the Taft Administrtion (1911). A year earlier Japan had sined a similar treary with Britain. As a result of Japan's industrualization, a very valuable trade relationship developed between the United States and Japan, benefitting both countries. America became the primary source of raw materials for Japan's expnding industry. At the time oil was not particularly important, but this changed after World War I. Oil became increasingly important in the inter-War era, both Japanese industry and the Japanse military. The Roosevlt Administrtion announced that it was terminating the 1911 Trade Trety with Japan. Given the importnce of the trade with America, this was avery significan step. And it signalled a a possible termintion of trade with the Empire. Japan did not change its policy in Chin, continuing its aggressive military campaign. The American press which because of Japanese atrocities was higlyfavorable to China. Thus the administration's action received generally favirable press treatment. The Isolationists were ot pleased, but were primarily focused on the administrations actions against Germany in Europe.

Roosevelt Administration Shifts (June 1940)

NAZI aggression in Europe, especially the fall of France caused dramatic shidts in Washington. President Roosevelt decided to run for an unprecedented third term. He also brought Republicans into his cabinent, especilly the military posts--the Secretary of war and Navy. The President appointed Republican Henry L. Stimson, who had been secretary of war under Taft and secretary of state under Hoover, secretary of war again (June 1940). Stimson was pure and simple a lion of an Anglophile and determined to save Britain in the face of opposition from the Usolationists. He also felt Japanese aggression had to be resisted. Stimson favored the use of economic sanctions to obstruct Japan’s advance in Asia. The President appointed Republican Frank Knox Secretry of the Navy. Knoox had been the Republican vice presidentil candidate in 1936. Hr and impson were in essence a kind og government of nationl unity. And becuse the heart of the Isolationist resistabce was in the Reoublican Party, their appointments undercut Isolationist opposition. Other important cabinent members, Treasury Secretary Henry Morgenthau and Interior Secretary Harold Ickes, strongly endorsed this policy. They and the President hoped that economic sanctions would prevent the Japanese from making a rash mistake by launching a war in the Pacific.

French Indochina (July-August 1940)

The French after the Japanese invasion of China permitted Nationalist China to land oil, trucks, and other war materiel in Haiphong and ship it to rail to Kunming in China. The Imperial Navy at the time was blockading Chinese ports not allready in Japanese hands. Using the port of Haphog in neutral French Indochina permitted the Chinese to evade the Japanese naval bloickade. Japan complained to the French government about the shipments to noavail. The Japanese had steadfastly refused to declare war on China, referring to the conflict as the China Incident. The French thus rejected the Japanese diplomatic notes. The frustrated Japanese military bombed the rail line (1939-40). Shipments thriygh Haiphong were substantial, about 10,000 tons of material, largely from the United States as of early 1941 were being shipped. The small rail link and the Japanese bombing limited actual deliveries. A pileup of material at Haiphong totaled 125,000 tons (June 1940). NAZI victories in Europe, especially the fall of France (May-June 1940), fundamentally changed the ballance of power. This presented opportunities for the Japanese. France was removed as a potential advisary. After the fall of Frrance to the NAZIs (June 1940). Japan saw an opportunity to establish a position in the French colony of Indochina. As a result of France's defeat by their Axis ally, the Japanese had the opportunity to move south without an actual invasion. The Japanese government presented the French Ambassador in Tokyo with a series of demands (June 19). Tokyo demanded that France immediately cease shipment of all war materiel to China and to amnit a Japanese Control Commission to regulate the border with China. Japanese troops massed on the Chinese border with Indochina and Imperial Navy ships sailed into the Gulf of Tonkin to demonstrate that these were no longr requests. The Japanese Government gave the French 48 hours to comply. The Japanese at the same time demanded that the British cease deliveries of war material to China over the Burma Road. An agreement was finally reached with the new Vichy Government which did not have the capability of resisting the Japanese (August 30). This allowed the Japanese to move military forces into the northern area of French Indochina (1940). A major goal of the Japanese was to cut off the flow of military supplies to China. The Japanese not only chieved that objective, but now could uae French airfiekds to bomb Chinese targets.

American Export Control Act (July 1940)

President Roosevelt signed the Export Control Act, authorizing the President to license or prohibit the export of essential defense materials (July 2, 1940). Under the authority of this new law, the President within weeks in response to Japanese actions in Indochina prohibited exports of aviation motor fuels and lubricants and No. 1 heavy melting iron and steel scrap (July 31). [Morgenstrern, pp. 322–23, 327–28.] The Roosevelt Administration embargoed exports of aviation gasoline and lubrication oil, scrap iron, and various strategic materials. It did not take the ultmare step, however, of embargoing crude oil. This was the step that would force Japan's hand and the President held back hoping that diplomacy could still divert the Japanese militarists from the path of war.

Axis Alliance (September 1940)

The Tripartite Pact was signed September 27, 1940. The agreement allied Germany and Italy (which were at war with Britain) and Japan (which was at war with China). Germany and Italy has since 1939-40 been at war with Britain. Japan since 1937 had been at war with China. The alliance did not require the partners to join these wars, but it did require them to come to each other's aid if attacked. The alliance became known as the Berlin-Rome-Tokyo Axis alliance, or commonly the Axis. The three Axis partners German hegemony over most of Europe; Italian hegemony in the Mediterranean, and Japanese hegemony in East Asia. After the Axis agreement was signed, several German allies joined the Axis, notably Vichy France and Fascist Spain refused to do so. Japan had no Asian allies, except or the puppet state of Manchukuo and THailand. The Axix provided allies and very powerful Allies indeed. Joining the Axis was seen in Japan as a way of presurin the United States. The Japanese militarists were in effect latching on to Hitler's star. Based on the phenomenal NAZI success, it made considerable success. The Japanese also made the calculation that the vast distances separating Germany from Japan in effect protected them from the new NAZI world order. Membership in the Axis, however, did not have the desired affect on the UNited States, either the American public or the Roosevelt Administration. Rather it confirmed in the American mind the criminal nature of the Japanese militarists. And with the Roosevelt Administation in harded vews toward Japan. America became less willing to offer diplomatic concessions in the on going negotiations.

Axis Alliance (September 1940)

Japan, Germany, and Itlay signed the Tripartite Pact (September 27, 1940). The agreement allied Germany and Italy (which were at war with Britain) and Japan (which was at war with China). Germany and Italy has since 1939-40 been at war with Britain. Japan since 1937 had been at war with China. The alliance did not require the partners to join these wars, but it did require them to come to each other's aid if attacked. The alliance became known as the Berlin-Rome-Tokyo Axis alliance, or commonly the Axis. The three Axis partners pursued German hegemony over most of Europe; Italian hegemony in the Mediterranean, and Japanese hegemony in East Asia. After the Axis agreement was signed, several German allies joined the Axis, notably Vichy France and Fascist Spain refused to do so. Japan had no Asian allies, except for the puppet state of Manchukuo. While the Axis powers sought to seek national goals through war and German and Japan especially liomuzed war, there proved to be remarkably little cooperation in wageing war. It would prove to be the Allies that waged war in a coordinated manner. The Anglo-American alliance, the two powers that had sought to avoid war would forge the most remarkable and successful alliance in the history of warfare. Ironically, the Axis despite the considerable military power of its member states proved to be a rather feable alliance. The major purpose, especially for Japan was to deter the Unites States. Here it failed uterly. And although there was one common enemy, the Soviet Union, the partners never made common cause. And here Japanese participation in the upcoming war with the Soviet Union almost certainly would have been decisive. Just as the NAZI-Soviet Non-Aggression Pact (August 1939) had left Hitler free to deal with the Allies, Japan signed its own Non-Agression Pact, the Japanese-Soviet Neutrality Pact (April 1941). This left the Japanese free to redeploy Manchurian forces south, but fatally for the Axis, it would allow the Soviets to redeploy Siberian forces west when the NAZIs struck.

Breaking the Japanese Diplomatic Code (September 1940)

American code breaking efforts played a major role in the Pacific War. The Japanese Foreign Office began using the Alphabetical Typewriter 97 (1938). American codebreakers referred to it as Purple. Purple was not an actual code, but an electro-mechanical coding system. It was a rotor machine like the Germans were using and like the Germans, the Japanese were convinved that the system could not be cracked. The U.S. Army Signals Intelligence Service (SIS) began to work on breaking into the system. Frank Rowlett directed the project. Finally Genevieve Grojan made a critical discovery. The SIS team was thus able to build a duplicate of a maxhine that they had never seen (September 1940). The American code breakers referred to the Japane encryption system as Purple and thus called the duplicate device the Purple Machine. The system was called Purple because of the color binders that were used for the decrypts. The messages were sent through machines and the American cryptologists managed to build their own Purple machine to read the Japanese diplomatic messages. The information gained from Purple decryptions came to be called Magic within the U.S. government because the Foreign Office used it for only their most important messages. [Curtin] The location of the Magic operation in Washington meant that information from the decrypts were not sent to Pearl Harbor unless the War Department decided to send some of the intelligence obtained. The Purple machine was a successor to earlier machines used to read Japanese diplomsatic mesages. The Japanese code system was designed by a Japanese Navy captain. Thus American officials were provide an insight into Japanese plans, albeit not military operations. American officials could thus read Japanese diplomatic dispatches in near real time. This is often misunderstood. Military plans were not transmitted on Purle. Decessions in Japan were made by the military and the nationlist military officers did not entirely trust the Foireign Office and certainly did not entrust them with military secrets. Much more important was the naval code which American cryptologists called JN-25. It was an enciphered code, producing five numeral groups iwhich was what was actually broadcasted. It proved more difficult to break than Purple. It was not until months after Pearl Harbor that the cryptologists at Pearl (Station Hypo) began breaking into JN-25. While it was only partially cracked. JN-25 decrypts played a major role in the Battle of the Coral Sea and the Battle of Midway.

America Expands the Embargo: Scrap Iron (October 1940)

The Roosevelt Administration in reaction to Japan joining the Axis, further expanded the list of embargoed items. Using the authority of the Export Control Act, he added scrap iron to the now growing list of embargoed items (effective October 16). The actual wording did not mention Japan, it was worded "all exports of scrap iron and steel to destinations other than Britain and the nations of the Western Hemisphere". The measure, however, was clearly aimed at Japan. The President still held back from the ulimate step, embargoing crude oil.

Japanese Strategic Weakness: Oil

Japan was almost totally dependant on imported oil, primarily from the United States which at the time was the leading producer. Japan imported about 90 percent of its oil. Japan had very limited oil fiekds and a small synthetic petroleum industry. And with an industrial economy and a large navy and merchant marine, Japan required large quantities of oil. The ongoing war in China also required oil. Japan's major source of oil was the United States. Before the invasion of China, Japan had been purchasing 80 percent of its oil in the United States (1937). The United States through its moral persuasion policy had suceeded in convincing American ship owners to reduce shipments to Japan without any formal action. Thus on the brink of war the Japanese were only obtaining 60 percent of theor oil in America (1941). The Japanese were importing American oil (along with Latin American and DEI oil) in Japanese and neutral country tankers.

American Economic Power (January-February 1941)

President Roosevelt understanding that the American people while sypathetic to Britain, the people of NAZI occupied Europe, and China realized that there was bo willingness to enter the War. They were willing to aid the victims of NAZI aggression, but not enter the war. So in the new year he took a series of decisions that would gave fsteful consequences. After hearing from Prime-Minister Churchill thatBritain was nearly babkrupt, he conceived the idea of Lend Lease. He appointed 'ardently anti-Axis" lawyer,' Dean Acheson as assistant secretary of state (January 1941). He then ordered the creation of a freezing committee composed of the secretaries of the State, Treasury, and Justice (February 1941). [Miller, p. 109.]

American Demands: Hull's Four Principles (April 1941)

Japanese diplomats met with German officials to discuss matters associated witn Axis Alliance. On the way back to Tokyo they stopped in Moscow to finalize a non-aggression pact with the Soviet Union. Only afew days after the sihning eremony in Moscow, Sectrtary of State Hull presented Ambassador Nomura a list of the four conditioins necessary to restore normal trade relations. They included: 1) respect for the territorial integrity of other countries, 2) noninterference in te internal affairs of other countries, 3) equal commercial opportunities, and 4) no territorial changes other than through peaceful negotiatiins.

Southern Indochina (July 1941)

The Japanese occupation of southern Indo-China was the turning point in the move toward war in the Pacific. A casual look at the map expolains just why. Southern-Indo-China points directly to the Southern Resourse Zone that Jaoan coveted (Malaya, Borneo and the Dutch East Indies. Bases in southern Indo-China could support ahd invasion of thgese areas which is preciselyvwhat occurred after Pearl Harbor. Brushing side American remonstrations, the Japanese conducted secret talks with the French colonial authorities in Indochina (July 1941). American officials learned of these talks through Purple intercepts. French diplomats also informed Washington of the Japanese demands. Japanese and Vichy French authorities reached an understanding regarding the use of air bases and ports in Southern Indo-China July 24). The Japanese thratened a military invasion if the French did not comply to ther demands. And of course Axus ally German occupied France. The Japanese immediately began to occupy southern Indochina. For the Roosevelt Administration, the Japanese move into southern Indochina meant Japanese rejection of Hull's Four Principles and a major military move. President Roosevelt had not been willing to take the key step, embargoing oil. The Japanese move made up the President's mind. One historian writes, "Much to the surprise of the Japanese leadership, within days of the occupationof southern Indochina, the US froze Japan's overseasc assetts, thereby denyigv the clater of the funds for purchasing raw materials from abroad .... As aresult, the Imperial forces were denied the resources they needed to peosecute theircwar effortv in China. Policy makers cin Tokyo were faced with then choiceof either fullfilling America's conditions for lifting the embargo, which was to withdraw the army from the Chinese mainland, or occupy the southern regions in ordere tobsecure new source of raw materials. Even then, the navy and the army disagreed over when to commence hostilities ...." [Ford]

America Freezes Japanese Assetts (July 1941)

With the Japanese occupation of southern Indochina and the revealing Purple intercepts indicating that the Japanese were untent on seizing the Southern Resource Zone, the Rosevelt Administratin began debating how to respond. The Cabinent was divided. Secretaries Morgenthau, Stimson, and Ickes argued for a real embargo that would really affect Japan--namely an oil embargo. The British were pushing for such an embargo. State Secretary Hull argued against an oil embargo. He was supported by the Navy Department which would have to fight a war in the Pacific. They argued that an oil embargo were tantamount to declaring war. They were right, but did not fully understand that the Japanese were moving toward war even without such an embrgo. President Roosevelt, understanding tha an oil embargo meant war, vacillated, not yet ready to make such a momentous decesion. Chief of Naval Operations, Admiral Harold Stark dispatched a formal memorandum to President Roosevelt clearly stating that an oil embargo meant war (July 24). That same day in the afternoon, Ambssador Nomura, President Roosevelt, Admiral Stark, and Under-Secretary of Stte Welles met in the White House. Roosevelt not yet aware that the Japanese had forced Vichy to consent to the occupation of southern Indochina, suggested to Nomura that an adiplomatic accomodation could be found on the basis of the neutralization of Indochina. He emphasized the key was that no Japanese occupation must take place. Roosevelt spoke openly to Nomura who he respectde. He explained that the United States had abstained from imposing an oil embargo because he had no desire to give Japan an excuse for seizing the oil fields of the oil-rich Dutch East Indies. He also explained that he could not justify continued oil deliveries to Japan if Japan was to continue agression. He said American public opinion would not accept this, especially with gasoline rationing. When Ambassador Nomura returned to the Japanese Embassy, he cabeled Tokyo expressing his opinion that American embargoes were eminent if the Japanese didn't accept the President's proposal on the neutralization of Indochina. The Japanese Government never responded. The Japanese move into southern Indochina finally convinced America that stronger action was needed. Southern Indochina brought the Japanese within striking range of the American Phillipine Islands, British Malaya and Singapore, and the DEI. The next American action was President Roosevelt issuing Executive Order 8832 (July 26, 1941). This froze Japanese funds in America. [Anderson] The United States issued its first list of blocked nationals (July 29). U.S. officials explained that the chief effect of the publication of the list of blocked na­tionals is to deny the benefits of inter-American trade to persons who have hitherto been using large profits to finance subversive activities aimed at undermining the peace and independence of the Western Hemisphere. . . . The issuance of the proclaimed list, marking persons who are contributing to these anti-American activities, is but another step in blocking the efforts of those who have sinister designs on the Americas."

American Military Moves (July 1941)

President Roosevelt had already move the Pacific Fleet forward from San Diego to Pearl Harbor, at the time a little known naval base. As a demonstration to Japan, the U.S. Pacific Fleet's fleet Fleet Problem XXI exercises were held off Hawaii (April 1940). The previous excercizes were held in the allsntic and Caribbean. It was an eight-phase operation for the defense of the Hawaiian area. Following the maneuvers, President Roosevelt ordered that Pearl Harbor would become the permanent base of the Pacific Fleet (February 1941). The Pearl anchorage was expanded to accommodate the entire fleet. Air bases and the air component were expanded. President Roosevelt realizing that economic persuasion was not moderatoing Japanese policy, also ordered a series of further military moves. The President nationalized the armed forces of the Philippines for the duration of the American emergency. He named General Douglas MacArthur the head of American-Filipino forces (July 26). He ordered squadrons of fighters and bombers to the Philippines. and he sent in motion the Americn Volunteer Group (AVG), the Flying Tigers to help protect Chinese cities from Japanese bombing.

Atlantic Charter (August 1941)

The Atlantic Charter is one of the key documents of the 20th century and remains still relevant today. President Roosevelt and Primeminister Churchill meet aboard the Prince of Wales on August 9-13, 1941 at Placentia Bay. The Prince of Wales had been badly mauled by Bismark in May. It was to be sunk by a Japanese aerial attack in December. Roosevelt and Churchill issued the Atlantic Charter. The two were acting as war time allies despite the fact that America was not yet ar war. Britain had weathered the worst that the NAZI Luftwaffe could throw at it. America and Britain were fighting the U-boats in the North Atlantic to keep Britain alive. It was clear that America would soon be drawn into the War. America had already played an important role in keeping Britain alive and the two countries were the only hope of the occupied European and in fact Western civilization itself--threatened by the evil tide of NAZI tyranny. The two leaders, the two most important men of the 20th century, agreed to a simple, but elegant eight-point statement of their aims which today still stands as the central credo of the Atlantic Alliance. This meeting and charter was in essence a strategian alliance against the Axis powers on the basis of these eight key princples. For the Japanese it was a clear statement that the war they were preparing to wage would be with both America and Britain.

Dean Achenson and Economic Policy

Dean Achenson was an important kawyer and committed Democrat. He work in Covington & Burling, a Washington, D.C. often involved with international legal issues. President Roosevelt upon assuming office appointed him Undersecretary of the Treasury (1933). When Secretary William H. Woodin fell ill, Acheson found himself acting secretary despite his lack of background in finance. And because he opposed the President core financial policy of deflating the dollar by controlling gold prices (fueking inflation), he was had to resign (November 1933). The President appointed his friend, Henry Morgethu Jr. as Secrtary thus ensuring that he Treasury would be fully onboard with his policies. (Actually Morgenthau who wanted tobbe Sctrtry of Agricultute may have had left baxkground in finance than Achenson. One wag at the time quipped thtthe President had managed to find the only Jew in Americaho kne nothing avnout finance.) Achenson went back to practicing law. With the approach of war, President Roosevelt tapped Achenson again, he headed a committee to study the operation of administrative bureaus in the federal government (1939-40). The President thsn appointed Acheson assistant secretary of state (January 1941). Acheson was an outspoken advocate of atoward the Axis. He became responsible for implementing much of United States economic policy to aid Britain and weaken Germany and he other Axis powers. Given the importance of this effort, he becme close to the President. Acheson helped implement the all-important Lend-Lease policy that helped keep Britin in the war and save the hard-pressed Soviet Union. Achenson also played a key role in the 1941 economic sansactions against Japan.

Oil Embargo (August 1941)

After freezing Japanese assetts, President Roosevelt departed Washington to meet with Primeninister Churchill off Newfoundland to sign the Atlantic Charter. The President froze all Japanese assets to disconcert them, not to drive then to war which he did not want. His focus was on Europe and did not want a two-front war. He held back from the ultimte step, the embargo of crude oil. He still hoped war could be prevented with Japan. While he was gone Assistant Secretary of State Acheson used the freezing of assetts to cut off creude oil exports to Japan (August 1). This was not what the President had wanted, but when he got back to Washington, he decided it would signal appear weakness and appeasement, so he did not reverse wht was in essence a de facto, but very effective oil embargo. This essentially meant a total trade embargo. Not only could Japan not buy oil and petroleum products (aviation fuel) in the United States, but it now did not havec the foreign exchange reserves to buy oil from other sources, even the DEI. To make the the American position crystal clear, President Roosevelt issued Executive Order ?????? (August 1). This order specifically banned the export of petroleum products to Japan. Britain, the Dutch Government in Exile, New Zealand, and the Philippines followed suit. With this stroke, Japan lost access to 75 percent of its overseas trade and nearly 90 percent of its imported oil.

Japanese Oil Requirements

Japan was using about 30 million barrels of oil (1941). This included domestic industry as well as military operations in China and very substantial naval training operations. The military usage was balanced in part by severe civilian gasoline rationing. The mikitary estimated that if war broke out that the country woukd need larger supplies, perhaps 33-35 million barrels. As with so many mikitary assessments, they were widely off on what war requirements would be. Japan after launching the Pacific War, conumed 52 million barrels (1942). The Japanese Navy alone consumed 30 million barrels. The American oil embargo was this a considerable threat. The Japanese had some time to work out the problem. They had built up a reserve of 50 million barrels which was equivalent to 1.5 years of their oil requirements. Without American oil, another source would be required and the source nearest Japan and within the ability of the Navy to seize was the DEI--the most important prize in what the Japanese called the Southern Resource Zone (SRZ).

Japanese Decision Making

The result was an oil shortage in Japan. The Japanese militarists were unwilling to change their policy of war in China and the oil embargo had the affect of convincing them that they needed to seize the oil rich Dutch East Indies (DEI) (Indonesia) to guarantee future supplies of oil. The DEI was virtually defenseless, but the small Dutch garison there was loyal to the Dutch Government in exile. The only major force standing between the DEI and the Japanese was the United States Pacific Fleet at Pearl Harbor and the British garison at Singapore.

American Support for China

Chiang Kai-Shek and the Nationslists after the Japanese invasion received little outside help at first. There was, however, considerable sympathy for China in America. Here Madame Chiang, a Chinese Christian and Wellesley graduate, played an important role. American support was a first diplomatic. This shifted to financial and eventually material support. Japan escalated its operations after the fall of France (1940) by seizing the French colony of Indo-China. The United States escalted its protests. The Pacific fleet was moved to Pear Harbor. American diplomatic protests escalated to embargoes of strategic materials. The United States implemented serious embargoes on oil and scrap metal. The oil enbargo was especially important and meant thast Japan would either have to withdraw from China or find another source of oil. This meant that Japan would have to declare war. The United States also began funelled supplies to the Chinese through Burma. In addition, the United States launched a secret effort to provided China a modern air defense--the American Volunteer Group (Flying Tigers). Its main task was to protect the Burma Road. President Roosevelt signed an executive order 1940 which permitted U.S. military personnel to resign so that they could participate in a covert operation to support China (May 1940). The All Volunteer Group formed became known as Chennault's Flying Tigers. This covert operation provide the Chinese a creditable air capability for the first time. The Flying Tigers did not, however, go into action until after Pearl Harbor. Their operations were legendary, but could not precent the Japanese from seixing Burma from the British. This cut off China from Allied assistance. The only exception was supplies which could be flown in over The Hump (The Himilayas) from India. This consisted primarily of supplies to support American air operations in China. American entry into the war, however, meant that Japan could no longer focus its military operations on China.


Anderson, Irvine H. Jr. "The 1941 De Facto Embargo on Oil to Japan: A Bureaucratic Reflex," The Pacific Historical Review Vol. 44, No. 2 (May, 1975), pp. 201-231. Published by: University of California Press.

Curtin, Matt. Brute Force.

Ford, Douglas. The Pacific War (2012), 288p.

Freidel, Frank. Franklin D. Roosevelt: Rendezuous with Destiny (Little Brown: Boston, 1990), 710p.

Miller, Edward S. Bankrupting the Enemy.

Morgenstern, George. “The Actual Road to Pearl Harbor,” in ed. Harry Elmer Barnes, Perpetual War for Perpetual Peace: A Critical Examination of the Foreign Policy of Franklin Delano Roosevelt and Its Aftermath (Caldwell, Id.: Caxton Printers, 1953). Critics of President Roosevelt charge that he was provoking the Japanese. This is probably a fair characterization, but the critics often do not provide a nuanced assessment. They rarely mentiined tht the President refrained from the key action, an embargo on crude oil until after it was clear that Japan had ddecided on war. They also do not mention that the President gave Japan n option, they could stop making war and withdraw from Indochina and China. Those were hardly aggressive demands.

Morison, Samuel Eliot. "The Rising Sun in the Pacific" History of United States Naval Operations in World War II Vol. 3.

U.S. Department of State. "Peace and War: United States Foreign Policy, 1931-1941," Publication No. 1983 (U.S. Government Printing Office: Washinton, D.C., 1943).

Williams, Benjamin H. "The coming of economic sanctions into American practice," The American Journal of International Law Vol. 37, No. 3 (July 1943), pp. 386-396. Published by: American Society of International Law


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Created: 10:50 PM 7/18/2016
Last updated: 3:17 AM 12/19/2018