The Trump administration’s detention of a green-card holder who was a leader in the Columbia University protests against Israel has put a face on the debate over immigration and the limits of free speech, with a sympathetic twist: The man, Mahmoud Khalil, is married to an American, and they are expecting their first child next month.

Khalil’s arrest could have a chilling effect on on- and off-campus protests involving people who aren’t citizens, said Columbia University immigration law professor Elora Mukherjee. Already, she said, it had provoked panic and fear among immigrant students on campus.

The clip shows plainclothes immigration authorities confronting the married couple in the lobby of their university-owned residence on the night of Saturday, March 8.