Washington — A federal judge on Tuesday threw out the Trump administration's challenge to a standing order issued by a U.S. district court in Maryland that bars federal immigration officials from immediately removing migrants who are challenging the legality of their detentions.

The decision from U.S. District Judge Thomas Cullen came in a novel and unprecedented lawsuit that the Trump administration filed against all 15 judges on the Maryland court in June. The Justice Department had argued that the standing order issued by Chief Judge George Russell in May was unlawful and outside the authority of the court.

The judges, represented by Paul Clement, who served as solicitor general under former President George W. Bush, sought to dismiss the lawsuit. They argued that the suit presented a dispute between two co-equal branches of government that could not be decided by the courts.

In a 37-page decision, Cullen agreed with the judges in finding that the Trump administration's challenge should be dismissed because, in part, the U.S. does not have the legal right to sue and the judges are absolute immune from the suit.

"Much as the Executive fights the characterization, a lawsuit by the executive branch of government against the judicial branch for the exercise of judicial power is not ordinary," he wrote. "The Executive's lawsuit will be dismissed, and its motion for preliminary injunction denied as moot. Whatever the merits of its grievance with the judges of the United States District Court for the District of Maryland, the Executive must find a proper way to raise those concerns."

Cullen said that if the Trump administration "truly believes" that the standing orders violate the law, it should pursue the paths laid out by Congress.

"Any fair reading of the legal authorities cited by Defendants leads to the ineluctable conclusion that this court has no alternative but to dismiss," he wrote. "To hold otherwise would run counter to overwhelming precedent, depart from longstanding constitutional tradition, and offend the rule of law."

The Justice Department plans to appeal the decision.

While the suit was filed in federal district court in Maryland, Cullen, who was appointed by President Trump to serve on the U.S. district court in Roanoke, Virginia, was assigned to preside over the case.

Cullen's ruling was not a surprise. In a hearing earlier this month in Maryland, the judge previewed his decision, telling Justice Department attorneys that the "far less destructive" move by the Justice Department would be to appeal the standing order in one of the cases where it had been issued, rather than sue another branch of the government to "accomplish its institutional interests." 

He echoed that position in his decision, writing that "under normal circumstances," it would not be a surprise if the government raised its concerns about the legality of the standing order through the mechanisms laid out by Congress.

"But as events over the past several months have revealed, these are not normal times — at least regarding the interplay between the Executive and this coordinate branch of government," Cullen wrote. "It's no surprise that the Executive chose a different, and more confrontational, path entirely. Instead of appealing any one of the affected habeas cases or filing a rules challenge with the Judicial Council, the Executive decided to sue — and in a big way."

In a footnote in his decision, Cullen criticized the Trump administration's repeated attacks on members of the federal judiciary who have ruled against the president's agenda. 

"Although some tension between the coordinate branches of government is a hallmark of our constitutional system, this concerted effort by the Executive to smear and impugn individual judges who rule against it is both unprecedented and unfortunate," Cullen wrote.

The standing order issued by Russell earlier this year prevents federal immigration officials from removing or altering the legal status of any migrant detainee who filed a habeas corpus petition for two business days.

The court adopted the order to address the rise in migrants in Maryland who were at risk of imminent deportation from the U.S. and sought review of their detentions. Signed by Russell, the chief judge, the order states that it aims to "preserve existing conditions and the potential jurisdiction" of the Maryland district court over pending matters, ensure immigrant petitioners can participate in court proceedings and have access to legal counsel, and guarantee the government has a "fulsome opportunity" to present its defense.

Among the judges named in the Trump administration's lawsuit was U.S. District Judge Paula Xinis, who is overseeing the legal cases filed by Kilmar Abrego Garcia, a Salvadoran man who has sued twice in the district over his March deportation and, most recently, confinement by immigration authorities. On Monday, Abrego Garcia filed a habeas petition challenging the legality of his detention by immigration officials. The court issued its standing order and temporarily blocked his immediate removal to a potential third-country, Uganda, where the Trump administration is attempting to send him.