The ruling from Kollar-Kotelly of the District of Columbia follows her earlier opinion blocking the president's ban on military recruitment of transgender men and women that possibly would have forced the dismissal of current service members starting in March.
"With only a brief hiatus, Defendants have had the opportunity to prepare for the accession of transgender individuals into the military for nearly one and a half years," since the policy was initially issued in June 2016, she wrote. "Especially in light of the record evidence showing, with specifics, that considerable work has already been done, the Court is not convinced by the vague claims in [the government's] declaration that a stay is needed."
A second federal judge in Baltimore also issued a preliminary injunction in November that goes further, preventing the administration from denying funding for sex-reassignment surgeries once the order takes effect.
Justice Department spokeswoman Lauren Ehrsam said in a statement that "we disagree with the Court's ruling and are seeking to stay the Defense Department's obligations under that ruling as we evaluate next steps."
In July, President Trump surprised military leaders and members of Congress when he announced the proposal in a series of tweets. Trump's order reversed an Obama-era policy allowing transgender people to serve openly and receive funding for sex-reassignment surgery.
In October, Kollar-Kotelly found challengers likely to prevail in asserting that the president's order violates equal-protection guarantees in the Constitution. The administration has appealed the ruling and in the meantime had asked the judge to temporarily postpone the recruitment requirement.
On Monday, Kollar-Kotelly noted that the government waited three weeks to appeal her Oct. 30 order barring the military from implementing a transgender ban, did not file its motion to stay the Jan. 1 deadline until Wednesday and has not sought any sort of expedited review of her initial decision.
"The Court notes that Defendants' portrayal of their situation as an emergency is belied by their litigation tactics," the judge wrote, adding, "If complying with the military's previously established January 1, 2018 deadline to begin accession was as unmanageable as Defendants now suggest, one would have expected Defendants to act with more alacrity."
In a statement, the Pentagon said it will comply with the court's order, while pursuing its appeal, writing that "DoD and the Department of Justice are actively pursuing relief from those court orders in order to allow an ongoing policy review scheduled to be completed before the end of March."
After the Jan. 1 start was cleared Monday, former Navy secretary Raymond Edwin Mabus Jr. said in a statement that allowing transgender candidates to enlist is not a complicated process and that nearly all the necessary preparation had been completed by the time he left office more than a year ago. "It is inconsistent with my understanding of the status of those efforts and the working of military personnel to conclude that the military would not be prepared almost a year later — and six months after the date on which the policy was originally scheduled to take effect," Mabus wrote.
Forcing the military to accept transgender applicants and implement such a significant change in policy may "negatively impact military readiness," government lawyers had said in asking for the delay.
Attorneys for the plaintiffs said in court filings that the military had already been preparing to accept transgender recruits. Before the change in administration, the Defense Department was gearing up to accept transgender applicants starting in July 2017 and had started training and other preparations.
"The government cannot credibly claim that it will be irreparably harmed by implementing a policy that it was on track to implement almost six months ago," according to the filing from the plaintiffs.
"This administration needs to stop creating fake problems and get on with it," GLAD transgender rights project director Jennifer Levi said after Kollar-Kotelly's decision Monday.