Irish immigration was met with a lot of backlash by Nativists. These people opposed any kind of immigration of people deemed harmful to their politics or ideology. This was what America was like, only accepting of foreign people who hold similar beliefs.
It was a war between Mexico and America for land. American wins the event with the power of the army and gains present day New Mexico, California, Arizona, and Nevada. The land gained in the war is then questioned if these states are to become free or slave states.
An act that allowed states to determine if they were to be free states or slave states. This gave some states an identity of what to say. It shaped the nation as one built on decision.
This was the election that Abraham Lincoln won without a single vote from the South. This angered many Southerners as they felt as though their vote didn't count. This made them rethink America, and how its supposed to be for the people and give them a say and choice.
The South thought they didn't have any power, so they seceded from the Union. The US lost half of its size and had become torn.This shaped affected their identity of unity and equal power among all the states.
America responded to rebellion states by freeing all the slaves in the South, making the war about ending slavery. This gave the US more power as lots of European countries backed off of the war. This made the US look more noble or important in its progressiveness.
This sentiment of hating immigrants carried over after the war, the only difference is that instead of it being political, it was economical. The number of Chinese immigrants was limited.