Events
1937
Japan goes to war with China
July1939
Roosevelt announces that Treaty of Commerce and Navigation will
not be renewed
July2, 1940
U.S. Congress passes Export Control Act
AugustJapan declares greater East Asia co-prosperity sphere
September27
Japan signs Tripartite Pact with Germany and Italy
January1941
Yamamoto prepares plan for attack on Pearl Harbor
JulyJapanese troops occupy Indochina
OctoberHirohito gives general approval for Pearl Harbor
attack
November8
Hirohito approves formal battle plan for attack in
December
November26
Japanese attack fleet sets sail from Japan
December7
Japan launches surprise attack on Pearl Harbor
December8
United States and Britain declare war on Japan
December11
Germany declares war on United States
Key People
-
Franklin D. Roosevelt
32nd
U.S. president; implemented economic penalties that angered Japan;
requested war declaration after Japanese attacked Pearl Harbor in
December 1941
-
Yamamoto Isoroku
Japanese admiral who planned surprise attack at Pearl
Harbor
-
Hirohito
Japanese
emperor; approved Pearl Harbor attack plan
-
Richmond K. Turner
U.S. Navy admiral; warned that navy be put on high
alert status and security increased at Pearl Harbor, but recommendations
were implemented only partly
Tensions in the Pacific
In the years prior to the outbreak of World War II in
Europe, tensions were also escalating in the Pacific region. Japan,
which had been at war with China since 1937,
had declared openly its intent to take over as much of eastern Asia
as it could. It also had serious ambitions toward taking territory
in the Soviet Union. If Germany, which the Japanese government saw
as a potential ally, would attack Russia from the west, Japanese
military leaders felt that they stood a good chance of seizing Soviet-controlled
territory in the east. The signing of the German-Soviet Nonaggression
Pact in 1939 therefore
caused a huge scandal in Japan, as it directly undermined Japan’s
plans.
Japan and the United States
In the meantime, the United States was becoming
more and more of a problem for Japan. Throughout the 1930s,
the United States and many European nations, suffering from the Great
Depression, enacted high protective tariffs. These tariffs
greatly curbed Japanese exports and heightened the effects of their
own economic depression. The poor economic conditions caused strong
anti-Western sentiment in Japan and were a strong factor in forcing
the Japanese invasion of China.
In July 1939,
President Franklin D. Roosevelt decided not to renew
the 1911 U.S.-Japan Treaty
of Commerce and Navigation, which was due to expire
in January 1940.
Then, on July 2, 1940, the
U.S. Congress passed the Export Control Act. Together,
these two actions effectively eliminated Japan’s primary source
of oil, scrap metal, and other material resources needed for war.
These developments dealt not only a severe economic blow
to Japan but also a humiliating slap in the face to Japan’s leaders,
who felt that the United States had no right to pass judgment on
them or to interfere in their affairs. Although Japan was still
smarting from the German-Soviet Nonaggression Pact, the United States’
actions were enough to overcome this resentment, and on September 27, 1940,
Japan signed the Tripartite Pact with Germany and Italy.
The pact made the three nations official allies.
The United States Prepares for War
Although the United States remained officially neutral
during the first two years of World War II, the Roosevelt administration
was far from indifferent or oblivious to the conflict. The United
States provided material support first to Britain and later to the
Soviet Union, secretly at first but then with increasing openness
over time. Chief among these measures was the March 1941Lend-Lease
Act,which empowered Roosevelt to give aid to
the Allies in exchange for whatever kind of compensation or benefit
the president deemed acceptable. The American people also paid close
attention to the events developing in the Pacific and, by mid-1941,
considered war with both Japan and Germany to be likely possibilities.
U.S. intelligence services had direct access to Japanese
coded transmissions, so U.S. officials were well aware that the
Japanese were planning something against them—they just did not
know precisely what. One man in particular, Admiral Richmond
K. Turner, strongly urged that U.S. forces be placed on a
higher state of alert, as he was particularly concerned about the
U.S. Navy base at Pearl Harbor, Hawaii. During previous
U.S. war games and exercises, Pearl Harbor had proven highly vulnerable
to surprise attacks. Although Turner’s advice was considered, only
some of his recommendations were implemented.
