How did growing nationalism affect foreign and domestic policies in the early 1800s

The main way in which growing nationalism affected foreign and domestic policies in the early 1800s in the US was that it made americans more assertive in the sense that they felt they could claim more land. This came to fruition during the Mexican-American War and the expansion of the US into the west. 

The second , larger puritan colony of massachusetts bay was conceived as a "city upon a hill". but it also struggled with internal turmoil like the salem witch trials and external conflicts like king philip's (metacom's) war.