The Justice Department is worried that without Supreme Court intervention, an ongoing court battle could allow transgender people to continue joining the military well into 2020, according to a new court filing.

The protracted fight could push the debate and legal fight over President Trump’s transgender military policy into the midst of the next presidential election and even into a new administration, according to attorneys for transgender plaintiffs.

Trump’s Justice Department laid out the concern in a new filing Thursday asking the court to lift an injunction and clear the way for Defense Secretary Jim Mattis to end the enlistments that began for the first time in January.

“Absent a stay, the nationwide injunction would thus remain in place for at least another year and likely well into 2020 — a period too long for the military to be forced to maintain a policy that it has determined, in its professional judgment, to be contrary to the nation’s interests,” according to the DOJ’s Thursday filing with the Supreme Court.

The president kicked off the legal fight and surprised many in the Pentagon and Capitol with tweets in July 2017 saying transgender troops would no longer be allowed to serve in any capacity due to “tremendous” medical costs and disruption.

Mattis has since said he has determined that transgender people who have been diagnosed with gender dysphoria or had gender transition surgery are unfit to enlist.

Trump has rarely mentioned transgender service since his tweets, but the legal fight could leave one of his most controversial defense policy decisions unresolved as he runs for re-election.

The 2020 field has yet to shape up, but House Democrats have already signaled they plan to make the policy a political issue when they become the majority in January.

“I’m going to try to combat discrimination within the military and I think that is a capabilities issue as well,” Rep. Adam Smith, D-Wash., who will be the new Armed Services chairman. “Because if we’re discriminating against transgender people or discriminating against women, there are a ton of jobs in the military that are crucially important that don’t have anything to do with physical fitness for that matter past a certain point.”

Service members and rights groups have been waging lawsuits for over a year against Trump and Mattis in four federal district courts, which have all granted injunctions blocking the new policy.

The Justice Department is now pinning its hopes of wrapping up the litigation on the Supreme Court.

Last month, it asked the court to rule in favor of Trump’s authority to set military policy as commander in chief. Plaintiffs, which include active-duty transgender troops, have to file their response by Christmas Eve, and the court is expected to decide by Jan. 18 whether to consider the case during its current term.

That “would presumably render a decision in this case by the end of June 2019,” the department wrote in its Thursday filing.

But the court could pass on the case and leave the Trump administration to continue the lengthy fight in the lower courts. In that case, DOJ has asked the court to lift the injunction so it can stop transgender enlistments during litigation.

“The Trump administration continues to try to sidestep the normal judicial process to implement a discriminatory, unconstitutional ban — already halted by four federal judges across the country,” said Jennifer Levi, a lead attorney for plaintiffs in two of the federal lawsuits and the transgender rights project director for the group GLAD.

Levi said the administration has presented “zero evidence” that transgender troops who are already serving have hurt the military’s readiness.