During a Thursday Fox Business appearance, Alabama Senator and gubernatorial candidate Tommy Tuberville announced that he’s introducing a bill to ban international students from Iran, China, and North Korea.

Tuberville recalled attending a recent graduation ceremony whose program, he said, included “40 Chinese nationals [getting] their degree in engineering and cyber,” leading him to the conclusion: “We are funding our own demise.”

“We have to do everything we possibly can to penalize universities that drop the ball on this agenda because if we don’t do that, we are not going to educate our kids,” Tuberville said.

The senator also claimed that international students are displacing American students, who “apply, but they can’t get in because there’s no slots for them, because of all the foreign nationals coming in.” To that end, he said his bill includes provisions to limit the total number of international students, while the focus is to keep students from rival countries out.

“We want to make sure we limit the number that comes in,” he said. “But we surely want to limit our adversaries. We want to do away with Iran, North Koreans, or Chinese nationals getting into this country and learning how to destroy the United States of America and our allies.”

Tuberville’s proposal to exclude students on the basis of national origin is so paranoid and nativist as to be absurd. A flood of North Korean students isn’t exactly a serious concern for the United States, which has, reportedly, not since the 2015–2016 school year welcomed a number of students from the People’s Republic that exceeds the single digits.

It’s also simply untrue that foreign students impede the education of American students, as evidence indicates that they are a great boon to the U.S. higher education system.

As the Brookings Institution notes, international students constitute a small minority of U.S. enrollment while contributing disproportionately to college and university budgets, namely in paying higher tuition. They also greatly support their surrounding communities. Removing international students, then, would hurt the economy, “add much to the trade deficit, harm many college budgets, and badly damage businesses in many college towns.”

Further, by subsidizing the cost of domestic students, “international students actually raise domestic enrollment,” according to a 2017 study by economist Kevin Shih, who analyzed periods where foreign enrollment underwent significant booms and busts. Shih estimates that when enrollment increases by 10 additional international students, domestic enrollment increases by about eight—a pattern that holds true as well for enrollment decreases.