Nativism was a belief among Americans that focused around being anti-immigration. Nativists felt that immigrants were ruining American society for multiple reasons including:
1) Taking jobs away from American citizens- Many immigrants were willing to work for less money in comparison to an American citizen. This was especially true for jobs in factories.
2) Refusal to assimilate- Many immigrants continued their traditions and religious beliefs when arriving in America. This preservation of culture worried many Americans.