Another kind of border wall in the U.S.

Acknowledging that many businesses have trouble getting by without foreign workers — as the president himself has found at his golf resorts in Florida and other properties — the Trump administration on Monday said it would grant 15,000 additional visas for low-wage seasonal workers in the next few months for firms that demonstrate that they would suffer “irreparable harm” without them.

In an administration that has led the chant to “Hire American,” it was a welcome sign that reality can trump sloganeering, at least in circumstances where corporate lobbying — in this case from the hospitality and fisheries industries, among others — reaches a fever pitch.

Simultaneously, however, the administration has been examining ways in which the United States can turn a much colder shoulder to the world, even if the consequences include “irreparable harm” not just for certain companies but also for the nation.

The most recent symptoms of the administration’s misgivings about America’s open society involve proposals to reassess procedures for foreign students already studying at U.S. colleges and universities and for visa-seekers overseas who would visit, work or seek refuge here.

Both proposals are impelled by fear, nativism and the use of national security as a pretext for indulging xenophobia.

As reported by The Post, officials at the Department of Homeland Security are formulating a plan that would impose new red tape on enrolled foreign students and the American colleges and universities where they study by forcing them to reapply to remain in the United States every year. Given the scale of that undertaking — well over 1 million foreigners are studying here, an all-time high — that’s a recipe for bureaucratic confusion and new annual fees whose combined effect would be to discourage students from coming to the United States and staying here.

That would sap the balance sheets of colleges and universities — and the country’s vitality. Foreign students injected more than $35 billion directly into the U.S. economy in 2015, according to the nonprofit Institute of International Education, and international students have an impressive track record in helping found successful start-ups.

They also play a critical role in sustaining the excellence of many American universities, which are alarmed by the proposal. Without foreign students — especially from China and India, the two biggest sources - many universities would struggle “to conduct research, recruit and retain teaching talent,” according to the National Foundation for American Policy, a nonprofit organization focused on higher education.

The administration also is considering shifting consular and visa-issuing functions, along with some 12,000 employees and $3 billion in fee revenue, to DHS from the State Department. Such a move would make the United States an international outlier. It would herald an era in which foreign tourists, business travelers and others would be treated automatically as security risks rather than as partners, allies and friends.

If the administration succeeds in turning the United States’ back on a globalized world, the result will be weakness and diminished leadership. Foreign students and visitors can and will go elsewhere, including to America’s rivals, which will be only too happy to reap the harvest of America’s decline.