San Francisco (AP) — A panel of appeals court judges reviewing President Donald Trump’s travel ban hammered away Tuesday at the federal government’s arguments that the states cannot challenge the order.

The hearing before the San Francisco-based 9th Circuit Court of Appeals judges was the greatest legal challenge yet to the ban, which has upended travel to the U.S. for more than a week and tested the new administration’s use of executive power.

The government asked the court to restore Trump’s order, contending that the president alone has the power to decide who can enter or stay in the United States. But several states have fought the ban on travelers from seven predominantly Muslim nations and insisted that it is unconstitutional.

The judges — two Democratic appointees and one Republican — repeatedly questioned Justice Department lawyer August Flentje on why the states should not be able to sue on behalf of their residents or on behalf of their universities, which have complained about students and faculty getting stranded overseas.

Circuit Judge Michelle T. Friedland, who was appointed by President Barack Obama, asked whether the government has any evidence connecting the seven predominantly Muslim nations covered by the ban to terrorism.

Flentje told the judges that the case was moving fast and the government had not yet included evidence to support the ban.

Friedland asked if the government had connected any immigrants from the seven countries to terrorism. Flentje cited a number of Somalis in the U.S. who, he said, had been connected to the al-Shabab terrorist group terror group after judges asked for evidence about the ban.

Flentje said the president has broad powers to protect national security and the right to assess risks based on the actions of Congress and his predecessor during the last two years.

The final minutes of the hearing were largely devoted to whether the travel ban was intended to discriminate against Muslims.

Judge Richard Clifton wanted to know how the order could be considered discriminatory if it potentially affected only 15 percent of the world’s Muslims, according to his calculations.

In response, Washington state Solicitor General Noah Purcell said that it’s remarkable to have this much evidence of discriminatory intent this early in the case. He cited Trump’s campaign statements about a Muslim ban and public statements by adviser Rudy Giuliani that he was asked to help devise a legal version of the Muslim ban.

A Justice Department lawyer argued that the courts should not question the president’s authority over national security based on newspaper articles. But under questioning from Clifton, he did not dispute that the statements were made.

Purcell said a previous ruling that halted the executive order has not harmed the U.S. government.

Instead, he told the panel, the order had harmed Washington state residents by splitting up families, holding up students trying to travel for their studies and preventing people from visiting family abroad.

Judge Richard R. Clifton said he suspects it’s a “small fraction” of the state’s residents.

The court was not expected to rule immediately, with a decision more likely to come later this week, court spokesman David Madden said.

Whatever the court eventually decides, either side could ask the Supreme Court to intervene.

Trump said Tuesday that he cannot believe his administration has to fight in the courts to uphold his refugee and immigration ban, a policy he says will protect the country.

“And a lot of people agree with us, believe me,” Trump said at a round table discussion with members of the National Sheriff’s Association. “If those people ever protested, you’d see a real protest. But they want to see our borders secure and our country secure.”

Homeland Security Secretary John Kelly told lawmakers that the order likely should have been delayed at least long enough to brief Congress about it.

The filing with the appeals court was the latest salvo in a high-stakes legal fight surrounding Trump’s order, which temporarily suspends the country’s refugee program and immigration from seven countries with terrorism concerns.

Washington state, Minnesota and other states say the appellate court should allow a temporary restraining order blocking the travel ban to stand as their lawsuit moves through the legal system.

If the case does end up before the Supreme Court, it could prove difficult to find the necessary five votes to undo a lower court order. The Supreme Court has been at less than full strength since Justice Antonin Scalia’s death a year ago. The last immigration case that reached the justices ended in a 4-4 tie.

How and when a case might get to the Supreme Court is unclear. The travel ban itself is to expire in 90 days, meaning it could run its course before a higher court takes up the issue. Or the administration could change it in any number of ways that would keep the issue alive.