December 7, 1941
Actually, it was largely because of the attack on Pearl Harbor. The US was already involved in the war financially, but they first deployed troops after that attack.
because they attacked Pearl Harbor
The US reaction was to counter attack. Commencing at Guadalcanal in 1942.
It was The US entered WW I on April 16th, 1917.
they now had to enter the 2nd ww on Dec.7 1941
With reference to December 7,1941, the results of the attack on Pearl Harbor was that the US entered WW 2. The US had to declare war on Japan. There was no decision on that. What was new was that Hitler then declared war on the US. The results of the first attack brought the US into a two front war.
Only Pearl Harbor. No other US city was attacked by Japan.
At the beginning of WW II the US hoped not to get involved. It was only after the US was bombed by Japan, at Pearl Harbor, that the US found that it could not avoid gettting involved.
20th century: 2nd Balkanic war, WW I, WW II
Woodrow Wilson was the president before and after the US entered WW I. The main reason for the US involvement was that German U-boats sank several US ships and other passenger ships that were carrying American passengers. THe US felt a natural kinship with Britain due to the large number of Americans with British ancestry and with France due to French aid in the American Revolution. The last straw was learning that Germany was negotiating to form an alliance with an anti-US faction that was contending for control of Mexico.
This question may pertain to WW 1, WW 2 or the Cold War. Using the latter as a reference, the US and over 20 other European nations, Canada and the US are allied with the treaty plan called NATO. An attack against one NATO member is considered an attack on all NATO members.
There was no battle that got the US into WW II. In Europe, we came to the aid of our allies, Britain and France, whom Germany had declared war on. In the Pacific Ocean, the Empire of Japan attacked Pearl Harbor in Hawaii, and sank all the battleships, there, and killed a number of military and civilian people, then declared war on the US. The US declared war on Japan, and thusly got into that part of the War.