A Columbia University graduate arrested for pro-Palestinian activism, a Brown University professor denied entry and deported after visiting her family in Lebanon, a Tufts University Ph.D. student snatched on the street on her way to Ramadan iftar by masked federal agents: In the past two weeks, we have watched in horror as scenes familiar from our studies of history have played out on and around U.S. university campuses.

Each of these individuals is or has been a U.S. lawful permanent resident or visa holder, and has been seemingly targeted for political speech that the government doesn’t like. Their persecution forms part of a frontal assault on higher education by the Trump administration designed to quash freedom of inquiry and expression. Never in our lifetimes have universities, one of the foundations of American democratic society, faced such an existential threat.

Harvard faculty recently established a chapter of the American Association of University Professors, a national organization founded in 1915 to advance academic freedom and “to ensure higher education’s contribution to the common good.” On Tuesday, the AAUP-Harvard chapter joined the national AAUP, AAUP-NYU, AAUP-Rutgers, and the Middle East Studies Association in suing the Trump administration to stop its campaign of “ideological deportation” against non-U.S. nationals.

“This is the first arrest of many to come,” crowed President Trump after the abduction of Columbia’s green-card-holding Mahmoud Khalil on March 8, essentially putting non-U.S. citizens on notice. The warning hits hard at Harvard. Roughly 15 percent of College students and over 30 percent of Graduate School of Arts and Sciences students are international; virtually every department has non-citizen faculty and staff members. The administration is wielding its power over individuals’ immigration status to coerce them into silence on political issues. And so far, the tactic seems to be working.