President Trump has directed most of his ire over his blocked executive orders on travel and refugees toward the Ninth Circuit Court of Appeals, the sprawling federal appeals court on the West Coast that he’s said should be “broken up.” But it’s not the only one mulling the latest order’s constitutionality.

The Fourth Circuit Court of Appeals heard oral arguments on Monday in International Refugee Assistance Project v. Trump, one of multiple cases challenging the second version of the executive order, which was issued in March. The lawsuit was filed by current visa holders who said they and their family members would be harmed if the order went into place, as well as by nonprofit organizations that work with refugees.

Many of the judges on the court, which covers Maryland, the Virginias, and the Carolinas, seemed skeptical of the Trump administration’s argument that the order should receive the broad latitude typically granted by the federal judiciary to the executive branch in national-security cases. Others sharply challenged the plaintiffs’ lawyer on whether his clients had the legal standing to challenge the portion of the executive order involving visa restrictions.

Jeffrey Wall, the principal deputy solicitor general, argued that the order should survive under a relatively lenient standard first articulated in Kleindienst v. Mandel, a 1972 Supreme Court case on barring communists from entry into the United States. That standard says that the government must only provide a “facially legitimate and bona fide reason” for certain immigration-related decisions—an easy burden for the executive branch to meet. The Trump administration has frequently insisted the order is necessary to protect the country from terrorism. Wall also said the revised order shouldn’t be considered a “Muslim ban,” as its critics have described it. “Its text doesn’t have anything to do with religion,” he told the judges. “Its operation doesn’t have anything to do with religion.”

Omar Jadwat, the director of the ACLU’s Immigrants’ Rights Project, represented the plaintiffs in the arguments. He frustrated some of the court’s judges at first by not giving clear answers on whether the order was facially legitimate, which could allow it to survive under the Mandel standard. But he later broadly rejected the idea that Trump’s order should be upheld on such a low judicial threshold. “Deference cannot be a license to violate the Establishment Clause,” he told the judges, referring to the First Amendment clause restricting the state’s ability to institutionalize religion.

The case challenged the president’s second iteration of the executive order, which temporarily barred visa travel from six Muslim-majority countries for 90 days and suspended the U.S. Refugee Assistance Program for 120 days. The order constituted a revision of a January 27 directive that banned travel from seven total countries, permanently banned Syrian refugees, and included an exemption for religious minorities. That order’s sudden implementation on a Friday night led to chaos at major American airports as foreign travelers permitted to enter the United States upon takeoff were blocked by the time they touched down.

After a three-judge panel in the Ninth Circuit Court of Appeals upheld a nationwide injunction blocking the order in February, the Trump administration backed down and issued a more narrowly tailored version in March. But the second version has still struggled in the courts. Judge Theodore Chuang, a federal district-court judge in Maryland, issued a preliminary injunction blocking its enforcement a few hours after it was supposed to go into effect on March 16. Justice Department lawyers had argued that the March order’s revisions addressed concerns by multiple federal courts about the first order’s scope and constitutionality.

Chuang ruled against them, citing public comments by White House Press Secretary Sean Spicer, who said that “the principles of the [second] executive order remain the same” as the first, and former New York City Mayor Rudy Giuliani, who told Fox News that Trump had asked him for help on how to create a Muslim ban that would pass legal muster.

“The second executive order does not explain specifically why this extraordinary, unprecedented action is the necessary response to the existing risks,” he wrote. “But while the travel ban bears no resemblance to any response to a national-security risk in recent history, it bears a clear resemblance to the precise action that President Trump described as effectuating his Muslim ban.”

A Justice Department appeal challenging Chuang’s injunction would typically be heard by a three-judge panel in the Fourth Circuit. But the circuit’s judges voted last month to hear the case in an en banc panel, a rare procedural maneuver that places the case for consideration before the court’s full 15-judge bench. (Thirteen of the judges heard the case on Monday after two of their colleagues recused themselves.)

The federal appeals courts could be a make-or-break stage of the legal process for the Trump administration. The day before Chuang’s ruling, Judge Derrick Watson in Hawaii issued a similar nationwide injunction blocking the order from going into effect. That case will be heard en banc by the Ninth Circuit Court of Appeals next week. If Trump loses in either the Fourth or Ninth Circuits, he would be unable to lawfully enforce the order’s key provisions unless the U.S. Supreme Court intervenes. A ruling in the Fourth Circuit could come as soon as this month.

Trump has frequently defended his orders as vital to national security, arguing on Twitter that “bad people” would enter the country without them and that the federal judiciary would bear responsibility for the next terrorist attack. But his critics have successfully convinced multiple judges that the order’s origins are instead linked to anti-Muslim animus, pointing to his initial call for a “total and complete shutdown of Muslims entering the United States” in December 2015.

Whether the president could somehow escape the taint of those calls was on at least one judge’s mind. “What if he says he’s sorry every day for a year?” Judge Dennis Shedd asked at one point during the oral arguments. “Would that do it for you?”

“Saying sorry is not enough,” Jadwat replied.