The State Department said Wednesday it has opened an investigation into Harvard University’s eligibility to host foreign exchange visitors, marking a new front in the Trump administration’s war with the country’s oldest college.

The department said it will probe whether Harvard’s handling of exchange visitors runs “contrary to our nation’s interests.”

“The American people have the right to expect their universities to uphold national security, comply with the law and provide safe environments for all students,” Secretary of State Marco Rubio said.

Exchange visitors are foreigners who are permitted to study at American universities under the J visa. They are similar to foreign students, who come under an F visa, but are generally part of a specific cultural exchange program.

More than a quarter of Harvard’s students are foreigners, most of them F or J visa holders.

Harvard has come under scrutiny by the Trump administration for its handling of anti-Israel protests in the wake of Hamas’ murderous 2023 sneak-attack on the Jewish nation.

Trump officials have demanded safety changes, but have also called for Harvard to revise its curriculum and hiring practices.

Previous moves to revoke Harvard’s ability to host foreign students — including a presidential proclamation from Mr. Trump himself — have been blocked by a federal judge, allowing the school to move ahead with plans to welcome a full contingent of foreign students this fall.

Judge Allison Burroughs, an Obama appointee to the court in Massachusetts, said the administration has been on an unfair campaign “to control a reputable academic institution and squelch diverse viewpoints.”

The cases are still developing.

Harvard, in a statement, confirmed it is still accepting foreign students and said it “is committed to continuing to comply” with the Exchange Visitor Program.

“This investigation is yet another retaliatory step taken by the Administration in violation of Harvard’s First Amendment rights,” the school said.

To come to the U.S. on a J visa a foreign citizen must work through an accredited exchange program. The government doles out those accreditations.

Mr. Rubio didn’t say how, exactly, he suspected Harvard is violating the terms of the program but ticked off the requirements for participation: compliance with regulations, transparency in reporting and a commitment to “the principles of cultural exchange and mutual understanding upon which the program was founded.”

• Stephen Dinan can be reached at sdinan@washingtontimes.com.