Why did the US join the war?

The us joined the war because Woodrow Wilson wanted to make the league of nations and create a safe place for democracy and economic growth. Major events like the Zimmerman Telegram and the sinking of the Lusitania

What aspect of the US involvement were subject for debate?

Entering the war was a large debate, and also the question if the US's economy could withstand the war.

What was the US's involvement like?

The Us was involved with the war for a short period of time, the war didn't have much of a cost on the US's economy. There was a large military struggle, but only for a few years.

How was the US affected by participation in the war?

The US's economy was boosted, and led into the roaring 20's. Made the US a major world force, and created the League of Nations to prevent wars like WW1 from happening again.