As of June 2017, approximately 1.16 million people, including 4,600 Americans, were included in the government database.

The United States government’s watchlist of more than one million people identified as “known or suspected terrorists'” violates the constitutional rights of those placed on it, a US federal judge ruled on Wednesday.

The ruling from District Judge Anthony Trenga in Virginia grants summary judgement to nearly two dozen Muslim US citizens who had challenged the watchlist with the help of the civil-rights group, the Council on American-Islamic Relations (CAIR).

But the judge is seeking additional legal briefs before deciding what remedy to impose.

The plaintiffs said they were wrongly placed on the list and that the government’s process for adding names is overly broad and riddled with errors.

The watchlist is disseminated to a variety of US government departments, foreign governments and police agencies.

In a statement, CAIR National Litigation Director Lena Masri described the decision as a “victory”.

“CAIR has a half-dozen other watchlist cases pending in federal courts across the country, and this opinion will pave the wave for our continued victories,” she said.

The FBI declined to comment on the ruling on Wednesday.

In court, the FBI’s lawyers argued that the difficulties suffered by the plaintiffs pale in comparison to the government’s interests in combatting “terrorism”.

Gadeir Abbas, a lawyer for the plaintiffs, called the ruling a victory. He said he would be asking the judge to severely curtail how the government compiles and uses its list.

“Innocent people should be beyond the reach of the watchlist system,” Abbas said. “We think that’s what the constitution requires.”

Trenga also wrote in his 31-page ruling that the case “presents unsettled issues.”

Infringement of due process

Ultimately, Trenga ruled that the travel difficulties faced by plaintiffs – who say they were handcuffed at border crossings and frequently subjected to invasive secondary searches at airports – are significant, and that they have a right to due process when their constitutional rights are infringed.

He also said the concerns about erroneous placement on the list are legitimate.

The watchlist, also known as the Terrorist Screening Database, is maintained by the FBI and shared with a variety of federal agencies.

Customs officers have access to the list to check people coming into the country at border crossings, and aviation officials use the database to help form the so-called no-fly list, which is a much smaller subset of the broader watchlist.

The watchlist has grown significantly over the years.

As of June 2017, approximately 1.16 million people were included on it, according to government documents filed in the lawsuit. In 2013, the number was 680,000.

The vast majority are foreigners, but according to the government, there were roughly 4,600 US citizens and lawful permanent residents on the watchlist as of 2017.

Abbas argued at a court hearing earlier this year that the intrusions imposed on those listed amounted to naught and that the list was worthless in terms of preventing “terrorism”.

He noted that Omar Mateen, the man who shot and killed 49 people at an Orlando nightclub in 2016, was on the list at one time, but then removed from it. Others who have committed “”terrorist acts” acts’ have never even been included.

The suit was filed in 2016, and has exposed previously unknown details about the list and how it is disseminated.

In particular, government lawyers acknowledged after years of denials that more than 500 private entities are given access to the list.

Government lawyers describe those private agencies as “law enforcement adjacent” and include university security teams, police forces, security forces and hospitals, railway companies and even animal-welfare organisations.