"I found myself explaining that, in addition to the Constitution, the United States is bound by international treaties. I explained that there are fundamental human rights that belong to everyone and apply in all countries in the world, including the United States, and that my work covers both."—Hina Shamsi, Director of the ACLU National Security Project, in an essay about how distressingly different her travel abroad has been since Trump's executive order banning Muslims from seven countries.
The person to whom she found herself explaining these facts was a Customs and Border Protection officer.
I strongly encourage you to read the whole thing.