The Supreme Court on Tuesday considered whether the Trump administration can bring back a border practice known as “metering,” a policy immigration authorities used to restrict access to asylum at the U.S.-Mexico border by limiting how many people could apply. The case arrived at the court as the Trump administration argued the practice remains necessary for managing periods when the border is at capacity, while advocates urged the court to keep in place lower-court rulings that found metering violated migrants’ rights.

During the arguments, Justice Brett Kavanaugh pressed the administration’s position. “Why would Congress privilege someone who illegally enters the United States?” Kavanaugh asked, questioning how the law should be read when people reach the border without legal authorization.

The administration defended the policy as a temporary capacity-management measure. Vivek Suri, an assistant to the solicitor general, told the court, “It’s saying our port is at capacity today, try again some other day,” arguing that those turned away on one day could seek asylum at a later time.

The justices also tested what the relevant statute requires officials to do and where those obligations apply. Chief Justice John Roberts questioned an attorney for migrants about exactly where someone must be to claim asylum, while Justice Ketanji Brown Jackson said the exercise was difficult because the policy is not currently in effect. “It just seems to me that we have a lot of hypotheticals regarding how this policy may have worked in the past, how it’s possibly going to work in the future, but we don’t have a policy in effect right now that we can actually rule on,” Jackson said.

At the center of the case is the Immigration and Nationality Act’s requirement that migrants who qualify must be able to apply for asylum after they “arrive in” the United States. The Justice Department argued that “arrive in” means people already inside the country, so it would not apply to those turned back on the Mexico side of the border. Immigration attorneys argued the law has long been read to mean anyone who comes to a port of entry must be able to apply.

Advocates urged the court not to restore a practice they said produced humanitarian harm during Trump’s first term. After arguments, Rebecca Cassler, an attorney for the American Immigration Council, said, “This life saving protection and more importantly, access to it is enshrined in our laws and has been for decades now.”

The policy’s history, as described during the proceedings, runs through multiple administrations. Metering was first used during Barack Obama’s administration when large numbers of Haitians appeared at the main crossing in San Diego from Tijuana, Mexico. It was expanded to all border crossings from Mexico during Donald Trump’s first term, and it ended in 2020 when the coronavirus pandemic led the government to impose greater restrictions on asylum seekers. Biden formally rescinded the use of metering in 2021, following rulings that found it unlawful.

A federal district judge, Cynthia Bashant, ruled in 2021 that metering violated migrants’ constitutional rights and a federal law requiring officials to screen anyone who arrives at the border seeking asylum. A divided U.S. appeals court affirmed that ruling, and nearly half of the judges on the full 9th U.S. Circuit Court of Appeals voted to rehear the case—raising the stakes for how the Supreme Court reads the statutory phrase at issue.

The metering case is among several immigration matters the Supreme Court is considering this term, including Trump’s push to end birthright citizenship for babies born to people in the U.S. illegally and the administration’s effort to strip legal protections for migrants fleeing instability and armed conflict.