They didn't?
You're thinking of World War II.
The Japanese attack of Pearl harbor
The U.S. entered World War II as a direct result of the bombing, by the Japanese, of Pearl Harbor on December 7, 1941.
It wanted to stay isolated. It did not want to get involved into a 'European' affair. The German sinking of the Lusitania was a reason the U.S. entered Worl War I and the Japanese bombing of Pearl Harbor, Hawaii was the reason the U.S. entered World War II.
The main reason for the breakout of the world war was that the heir to the austrian-hungary throne was assassinated in Siberia. Austria laid down 10 conditions in front of Siberia which Siberia declined .Germany entered to show their support for Austria and Russia entered for Siberia. The war soon spread throughout Europe and was known as the first world war
The United States entered World War II after the Japanese attack on Pearl Harbour on 7th December 1941. The US declared war on the following day, 8th December 1941.
they started it
The US entered the war for a variety of reasons
pearl harbor
The Japanese attack of Pearl harbor
The US entered World War II after the Japanese attacked Pearl Harbor December 7, 1941.
The Japanese entered Singapore via the Causeway from Malaysia. This caught the British off-guard as the British always prepared for a war from the seas.
The Japanese bombed Pearl Harbor
Economic coercion
The US entered World War 2 on 8 December 1941 - the day after the Japanese attack on Pearl Harbour.
They entered the war on December 8th, 1941 after the Japanese bombed Pearl Harbor on December 7th, 1941.
Most directly, the US entered World War II.
4th December 1941 The day after the Japanese attack on pearl harbour