Over two days last week, the Trump administration announced two measures targeting international students and scholars who make up a large share of the U.S. biomedical research workforce. The Department of Homeland Security proposed a $70,000 fee for a work authorization program commonly used by foreign students, and the Labor Department said it is investigating nine universities—including Harvard, Stanford, and Yale—for alleged fraud related to visas for postdoctoral researchers.

These actions come alongside other administration efforts: DHS is fighting in court to impose a four-year cap on graduate student and postdoc stays, and it is trying to revive $100,000 fees for H-2B visas used by high-skill workers in biotech. None of the changes have taken effect, but experts say the repeated attempts are already deterring students.

According to a survey by the Association of American Universities, domestic applications to U.S. Ph.D. programs rose 3% this year while international applications fell 21%. "This is an incredible series of self-owns," said Elizabeth Goss, a Boston immigration attorney. "The government also knows that none of this will stand up in court. They just want to send a message: Don't come here."