Short answers, pulled from the story.
American nationalism is a form of nationalism in the United States that views Americans as a nation whose interests should be represented by the U.S. government. It can take civic, ethnic, cultural, or economic forms, and it encompasses efforts to reinforce national identity and self-determination in both domestic and international affairs.
The first Naturalization Act of 1790, signed into law by George Washington, limited citizenship to free white men of good character. It denied citizenship to enslaved Black people and anyone of non-European descent, making it a form of ethnic nationalism from the country's founding.
In an 1858 speech, Lincoln argued that the Declaration of Independence served as an electric cord linking people of all ethnic backgrounds to the nation's founding principles. He said immigrants without blood ties to the founders could still claim kinship through the Declaration's statement that all men are created equal.
In a 2016 paper in the American Sociological Review, Bart Bonikowski and Paul DiMaggio identified four groups: the disengaged (17% of respondents), creedal or civic nationalists (22%), ardent nationalists (24%), and restrictive nationalists (38%), the largest group.
World War II produced what historians describe as unprecedented nationalism in the United States. After the 1941 attack on Pearl Harbor, Americans enlisted in large numbers and organized daily life around the war effort through rationing, volunteer work, and income saving. Even members of pacifist churches and anti-war groups set aside their opposition, viewing the conflict as a just war.
President Donald Trump embraced the label of nationalist, and several officials in his administration were identified as representing a nationalist wing, including Steve Bannon, Stephen Miller, and Peter Navarro. A February 2017 article in The Atlantic described the movement as populist economic nationalism modeled on 19th-century President Andrew Jackson's populism, with Miller and Bannon credited as architects of that framing.