The Supreme Court issued an unsigned order on Wednesday evening that effectively closes the United States’ southern border to nearly all Central American asylum seekers.

The decision stays a lower court decision blocking a Trump administration policy that seeks to halt nearly all asylum applications from these migrants and allow the US government to require them to seek asylum in countries they travel through. The government will now be allowed to enforce the policy while legal challenges move ahead.

The administration’s rule, issued on July 16, says that almost any foreign national who arrives at the southern border may not seek asylum if they crossed through another nation to get here. There are a few limits — a migrant can seek asylum in the United States if they complete a potentially onerous legal process in another country, for example, or if they were “severe” trafficking victims — but the practical effect of the rule is to ban most migrants from seeking asylum.

Federal law allows any foreign national “who is physically present in the United States or who arrives in the United States” to seek asylum, a form of mercy that allows people who fear persecution in their home nation to remain in the United States. Though the asylum statute does contain some limited exceptions, no explicit provision provides for the sweeping asylum restrictions implemented by the Trump administration.

Ordinarily, when the executive branch pushes out a new regulation, it must first submit that regulation to a process that allows the public to comment on the proposed rule. The Trump administration did not follow that ordinary process when it pushed out its asylum ban.

Because the Supreme Court’s order is not signed, it is not clear why the Court decided to stay the lower court’s order or which justices voted for this outcome. Only two members of the Court, Justices Ruth Bader Ginsburg and Sonia Sotomayor, registered public dissents.

“It is especially concerning,” Sotomayor writes in a dissenting opinion, which Ginsburg joined, “that the rule the Government promulgated topples decades of settled asylum practices and affects some of the most vulnerable people in the Western Hemisphere—without affording the public a chance to weigh in.”