A panel of US federal appellate judges expressed concerns about ordering wholesale changes to a government watchlist, also known as the Terrorism Screening Database, of roughly 1 million individuals labeled as “known or suspected terrorists,” despite a lower court finding that the list was constitutionally flawed.

The 4th US Circuit Court of Appeals in Richmond, Virginia, heard arguments Tuesday on the constitutionality of the watchlist.

Government lawyers urged the judges not to intervene in the executive branch’s administration of the list and its national security judgments.

Fundamentally, they said the problems encountered by those on the list, like enhanced screening at airports and delays at border crossings, were too insignificant to merit intervention on constitutional grounds. They said many Americans experience such delays during travel, often at random.

Gadeir Abbas, a lawyer with the Council on American-Islamic Relations, which brought the suit on behalf of roughly two dozen Muslim clients, said the burden faced by those on the list is far from insignificant. He cited accounts from plaintiffs of being shackled and having guns pointed at them in front of their children at border crossings when agents encountered their names in the database.

“They are not just inconveniences,” Abbas said.

But J. Harvie Wilkinson, one of three judges who heard the case, said that while some plaintiffs experienced significant issues, others experienced only minor problems. He suggested it might be better for individual plaintiffs to file suits based on their own experiences, rather than just attacking the watchlist as a whole.

He also questioned whether the judiciary branch was able or qualified to require revisions to a program that the government insists is vital to national security.

“We’re being asked to take a highly sensitive and, as far as I know, important program … and devise a remedy with unknown consequences,” Wilkinson said. “We would be wading into deep, treacherous and uncharted waters here.”

Government lawyers have insisted the program is vital to national security. They said in court papers that the government uses the database to help determine whether to place air marshals on certain flights, for example. They also emphasized that while the list has been known to contain more than 1 million names at times, fewer than 5,000 of those people are US citizens.

The lawsuit was filed in 2016. In 2019, US District Judge Anthony Trenga in Alexandria ruled in favour of the plaintiffs, prompting the appeal. Trenga ruled that the travel difficulties faced by plaintiffs and their concerns about erroneous placement on the list are legitimate.

The judges in Tuesday’s hearing also had some tough questions for the government. Wilkinson said the lack of due process for people who believe they are wrongly placed on the list is troubling.

“Normally when the government deprives you of a right, they let you know what they’re doing,” Wilkinson said.

All three judges who heard the case are GOP appointees – Wilkinson was appointed by former President Ronald Reagan and the other two were appointed by former President Donald Trump.

A ruling is expecting in several weeks.