The Supreme Court grappled Tuesday with whether the Trump administration should be able to revive an immigration policy that has been used to turn back migrants seeking asylum at the U.S.-Mexico border.

Some conservative justices seemed receptive to the Justice Department's push to overturn a lower-court ruling against the practice known as metering. Immigration authorities limited the number of people who could apply for asylum, saying it was necessary to handle an increase at the border.

Advocates say the policy created a humanitarian crisis during President Donald Trump's first term as people who were turned away settled in makeshift camps in Mexico as they waited for a chance to seek asylum.

The policy isn't in place now, and Trump ordered a wider suspension of the asylum system at the start of his second term.

The administration, though, argues that metering remains a “critical tool" used under administrations from both parties, and should be available if necessary in the future.

Some justices seemed open to that argument, though others raised questions about whether the policy would allow people who entered the country illegally to apply for asylum while new arrivals seeking legal entry at the border could be blocked.

“Why would Congress privilege someone who illegally enters the United States?” Justice Brett Kavanaugh asked.

An attorney for the Trump administration maintained that people turned away one day could potentially come back later. “It's saying our port is at capacity today, try again some other day,” said Vivek Suri, assistant to the solicitor general.