On Tuesday, masked federal agents abruptly confronted Rumeysa Ozturk, a Turkish doctoral student at Tufts and a Fulbright scholar on the sidewalk, took her phone, and swept her into an unmarked vehicle. They refused to clearly identify themselves, showed no warrant or badges, and did not tell her why she was being arrested. Despite a court order that she remain in Massachusetts, she is being held in Louisiana in violation of the US Constitution’s guarantee of due process. Her student visa has been cancelled.