On the surface, “un-American” implies consensus: It carries a punch only when everybody agrees what “American” is. But the word has historically gained traction at moments when national consensus seems the most wobbly and uncertain. It signals an urgent desire to find something — anything — that Americans can still agree on.
For Trump’s critics, it is aspirational, pointing toward an American dream of liberty and equality that has never quite been realized on the ground. For the administration, the word is a way of designating insiders and outsiders, the righteous and the nonrighteous, those who deserve the privileges of citizenship and those who do not. Coming from the White House, it also carries an implied threat: Those who are “un-American” — leakers, critics, reporters — may need to be dealt with as “enemies of the people,” another worrisome Trump phrase.
To label something “un-American” is to imagine America as it should have been or as it might yet be but not as it ever was. Far from bringing back a meaningless insult, the revival of the charge suggests that something very big is now at stake: not only the direction of federal policy or the partisan balance of power but America’s identity as a nation.
Beverly Gage, “Second Nature”, The New York Times Magazine (26 March 2017), 12.