Protesters gather in front of the White House amid mounting legal challenges to President Donald Trump’s transgender military ban. (Paul J. Richards/AFP/Getty Images)

A federal appeals court on Thursday declined to delay a requirement that the U.S. military begin enlisting qualified transgender men and women for the first time starting Jan. 1.

The U.S. Court of Appeals for the 4th Circuit refused to grant the Trump administration's request to temporarily block an earlier order that the military accept transgender recruits, potentially propelling the issue to the Supreme Court in the coming days.

The ruling was another legal blow for the president, who surprised military leaders when he announced in July in a series of tweets that the U.S. government "will not accept or allow transgender individuals to serve in any capacity in the U.S. Military."

His order reversed an Obama-era policy allowing transgender people to serve openly and receive funding for sex-reassignment surgery. That order was promptly challenged in federal court by active-duty transgender service members who say it violates their Fifth Amendment rights to equal protection.

The one-page order from the 4th Circuit upholds a preliminary injunction issued by a lower court judge in Baltimore, one of three judges to rule against the administration's policy. The government has emergency appeals pending in the two other cases from D.C. and Seattle, but the injunction from Baltimore applies nationally.

To get around the 4th Circuit order from Judges Diana Gribbon Motz, Albert Diaz and Pamela A. Harris, the government would need to prevail at the Supreme Court.

Justice Department spokeswoman Lauren Ehrsam said Thursday, "We disagree with the court's ruling and are currently evaluating the next steps."

The Trump administration's plan that was set to take effect in March would have blocked military recruitment of transgender people, barred military funding for sex-reassignment surgery and possibly forced the dismissal of current transgender service members.

Justice Department lawyers have said the lawsuits are premature because the policy is on hold pending a review by the Defense Department, and they say no decisions have been made about whether to discharge active-duty service members solely because they are transgender.

In asking the court to delay the Jan. 1 start date, government lawyers said the timetable imposed by the lower court would be too burdensome on the armed forces and require training for thousands of recruiters and personnel responsible for providing medical screenings.

Even as the Justice Department has appealed the series of unfavorable rulings, the Defense Department on Dec. 8 issued detailed policy guidance to military recruiters for how to enlist transgender men and women.

Attorneys and advocates for transgender service members said in court filings that the memo undercuts the administration's assertion that it is struggling to prepare.

In the D.C. case, U.S. District Judge Colleen Kollar-Kotelly initially issued a preliminary injunction in October finding that the challengers were likely to prevail in asserting that the president's order violates equal-protection guarantees in the Constitution.

In her subsequent ruling this month declining to postpone the start date for accepting transgender recruits, Kollar-Kotelly said the government has had nearly a year and a half to prepare to enlist transgender men and women.

In the Maryland case, U.S. District Judge Marvin J. Garbis went further than Kollar-Kotelly by blocking the administration's ability to deny funding for gender reassignment surgery. In his ruling, Garbis wrote that transgender service members have "demonstrated that they are already suffering harmful consequences."