New Jersey has joined a multistate coalition that is challenging the Trump administration’s proposed ban on transgender people serving in the military.

The lawsuit, filed U.S. District Court’s Western District of Washington in Seattle, will seek to have the ban declared illegal, according to New Jersey Attorney General Gurbir Grewal.

Fifteen states and the District of Columbia are involved in the suit.

“[President Trump’s] ban doesn’t just demean our armed forces, including the many brave transgender soldiers who have served openly and with great distinction…[it] also violates the Constitution,” Grewal said in a statement.

“We cannot allow President Trump’s policies to keep brave, patriotic Americans from serving in our military,” Gov. Phil Murphy also said in the statement.

President Trump first announced the proposed ban on Twitter this past July.

“Our military must be focused on decisive and overwhelming victory and cannot be burdened with the tremendous medical costs and disruption that transgender in the military would entail,” the president posted.

The ban was quickly met with opposition by LGBT advocates and was delayed.

Pentagon officials said in December that transgender recruits would be allowed to enlist in the military coming Jan. 1 while the fate of the ban was being decided.

Approximately 150,000 veterans, active-duty service members, and members of the National Guard or Reserves identify as transgender, according to Grewal’s news release.