Like other nations born in anti-colonial revolutions, the United States faced the challenge of building a sound economy, preserving national independence, and creating a stable political system which provided a legitimate place for opposition. In 1790, it was not at all obvious that the Union would long survive.
It did happen, and it was something to do with pilgrims and Indians making peace, and accomplishing a deal
The US joined world war 1 because:
1) sinking of the Lusitania
2) the Zimmermann telegram
hope this helps
