Your birth certificate and passport are the most important documents there are to account for your citizenship. These are “the papers” you show the jackboots. There is no higher standard of proof.
Thanks to the lunatic fringe (entire Republican party) we all got a front row seat to the power of an American birth certificate in proving ones citizenship!! It was fun watching the rightwing knuckle draggers squirm when Obama finally confronted their conspiracy prone predilections (Benghazi, anyone?) by releasing his birth certificate!
You’d normally think that the problem of “showing your papers” wouldn’t be an issue that would come up for a couple of middle aged white folks attending an historically Black college in the heart of Dixie. Normally you’d probably be right. But nothing is ever normal down south.