The American Civil Liberties Union (ACLU) on Thursday asked a federal judge to block President Donald Trump's ban on transgender troops.

In July, Trump tweeted his call for a complete ban on transgender troops. Roughly a month later, the White House issued guidance on implementing Trump's ban, in which Trump claims that the Obama administration “failed to identity a sufficient basis” to end the military ban – which was rolled back in June, 2016 – and orders the Pentagon to reinstate the policy, arguing that transgender people are a “disruption” to the military.

Joshua Block, senior staff attorney with the ACLU's LGBT Project, said in a statement that the ACLU was asking the court “to reinforce what we already know to be true, which is that President Trump's shameful, impulsive decision to ban transgender people from serving in the military is blatantly unconstitutional.”

ACLU lawyers asked the court to issue a preliminary injunction on behalf of six current members of the armed forces who are transgender: Petty Officer 1st Class Brock Stone, Senior Airman John Doe, Airman 1st Class Seven Ero George, Petty Officer 1st Class Teagan Gilbert, Staff Sgt. Kate Cole, and Technical Sgt. Tommie Parker.

The ACLU argued that the ban violates constitutional guarantees of equal protection and substantive due process as well as the statutory right to medical care that all service members enjoy.

“Trans service members like me have earned the privilege of continuing to serve our country so long as we continue to be fit for duty,” said plaintiff Brock Stone. “We are equal to the task, and it is our right to have an equal chance to take that task on.”

The ACLU's case is one of three challenging the ban. Last month, a federal judge agreed with plaintiffs seeking to halt the ban.

(Related: Judge blocks Trump's ban on transgender troops.)