SEATTLE — A lawyer for President Donald Trump’s administration faced tough questions Monday from three federal appeals court judges over who should be allowed into the U.S. under the travel ban affecting six mostly Muslim nations.

In June the U.S. Supreme Court said the president’s 90-day ban on visitors from Iran, Libya, Somalia, Sudan, Syria and Yemen can be enforced pending arguments scheduled for October as long as those visitors lack a “bona fide relationship with a person or entity in the United States,” such as a close family relationship.

The government interpreted such family relations as including immediate family members and in-laws, but it excluded grandparents, cousins, aunts and uncles. A judge in Hawaii overruled that interpretation, expanding the definition of who can enter. The administration appealed that order to the 9th Circuit Court of Appeals, which heard arguments in Seattle Monday.

The judges grilled Justice Department lawyer Hashim Mooppan. Judge Ronald Gould asked “from what universe” the government got the idea that grandparents don’t constitute a close family relationship.

Judge Richard Paez questioned why an in-law would be allowed in, but not a grandparent.

“Could you explain to me what’s significantly different between a grandparent and a mother-in-law, father-in-law?” Paez asked. “What is so different about those two categories? One is in and one is out.”

Mooppan said parents-in-law are only one step removed from the family unit, while a grandparent or grandchild is more than one step removed. He said the government wasn’t disputing that people could have a profound connection to their grandparents, but the administration was relying on a standard set by Congress to come up with a workable definition.

“It can’t just mean all family except the most distant,” he said.