Neutrality Acts and Isolationism:
- As World War II broke out in Europe in 1939, the United States initially pursued a policy of neutrality.
- The Neutrality Acts had been passed in the 1930s to keep the country out of foreign wars.
- The sentiment in the United States was to avoid direct involvement in conflicts overseas, as it had in World War I.
Lend-Lease Act:
- In 1941, the US passed the Lend-Lease Act, which allowed President Franklin D. Roosevelt to provide military aid to Allied powers (mainly Great Britain) without directly entering the war.
- The Aid included war supplies, munitions, and ships, all on a Lend-Lease basis, meaning the recipients would pay for them after the war.
Attack on Pearl Harbor:
- On December 7, 1941, Japan launched a surprise attack on the US naval base at Pearl Harbor in Hawaii.
- This act of aggression resulted in the United States declaring war on Japan, officially entering World War II.
Declaration of War:
- Four days after the Pearl Harbor attack, Germany and Italy declared war on the US, further solidifying the country's involvement in the conflict.
"Europe First" Strategy:
- The United States, along with its allies, adopted a "Europe First" strategy, prioritizing the defeat of Nazi Germany before taking on Japan in the Pacific.
Allied Cooperation:
- Throughout the war, the United States collaborated closely with Allied forces, including the United Kingdom, France, the Soviet Union, and other nations, to collectively oppose the Axis powers.
Military Presence and Operations:
- The US contributed its military forces to various theaters of war, including Europe, North Africa, and the Pacific.
- American troops played crucial roles in major battles, such as D-Day, the Battle of the Bulge, and the island hopping campaign against Japan in the Pacific.
Industrial and Economic Contributions:
- The United States' robust economy and industrial capacity proved vital in supporting the Allied war effort.
- American production of war materials and supplies played a significant role in aiding its own forces and those of its allies.
Manhattan Project and Atomic Bombs:
- The US led the secret Manhattan Project, which developed and produced the atomic bomb.
- The United States dropped atomic bombs on Hiroshima and Nagasaki in Japan in August 1945, leading to the surrender of Japan and the effective end of World War II.
Wartime Diplomacy:
- The US played a pivotal role in international diplomacy during the war, notably through the Casablanca Conference, the Tehran Conference, and the Yalta Conference, where Allied leaders discussed war strategy and postwar plans.
Postwar Influence:
- The United States emerged from the war as a major world power, playing a central role in shaping the postwar international order and global institutions, such as the United Nations.