President Trump on Friday directed the Pentagon to ban the recruitment of openly transgender people, but is leaving it to military leaders to determine whether individuals already in the armed forces should be allowed to continue to serve.

The presidential memorandum signed by Trump will also prevent the military from providing medical treatment for sex- reassignment surgeries.

Trump is reversing an Obama administration policy that was the latest step in the advancement of rights for lesbian, gay, bisexual and transgender people in the U.S. military in recent years. But the White House said Trump thinks his predecessor failed to provide sufficient basis to determine whether terminating the Defense Department’s long-standing policy on transgender individuals would “hinder military effectiveness and lethality, disrupt unit cohesion, or tax military resources.”

The memorandum states that “further study” is necessary to ensure that the policy change will not have negative effects on military readiness.

In June 2016, President Barack Obama allowed transgender soldiers to serve openly and receive related medical treatment, while ordering the Pentagon to determine a policy for allowing transgender people to join the armed forces within a year.

President Trump's tweeted transgender military ban on July 26 drew immediate criticism from both Democrats and Republicans, who were caught unaware by the decision. (Jenny Starrs/The Washington Post)

But Defense Secretary Jim Mattis earlier this year delayed the entry of transgender troops until January 2018, citing the need to further evaluate the impact on the military’s “readiness and cohesion.”

The memorandum comes weeks after Trump abruptly announced the ban in a series of tweets July 26. It was not immediately implemented by the military, which said it would wait for further guidance from the White House.

“After consultation with my Generals and military experts, please be advised that the United States Government will not accept or allow transgender individuals to serve in any capacity in the U.S. Military,” Trump tweeted. “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.”

Trump’s initial announcement was greeted with criticism from Democrats and Republicans, many of whom said it was discriminatory toward transgender people willing to volunteer to serve their country.

“Any American who meets current medical and readiness standards should be allowed to continue serving,” Sen. John McCain (R-Ariz.) said in a statement issued after Trump’s Twitter announcement of the ban. “There is no reason to force service members who are able to fight, train and deploy to leave the military — regardless of their gender identity.”

The memo released Friday gives the Pentagon six months to determine how to implement Trump’s directive as it relates to transgender people currently serving. Until that determination is made, no action will be taken against any individuals, the memo states. That plan will be implemented by March 23, 2018.

A senior administration official defended the president’s actions in a call with reporters Friday, saying the decision was made based on national security concerns. 

President Trump spoke about banning transgender people from the military in Bedminster N.J. on Aug. 10. (The Washington Post)

“The basis for this directive is very much our national security needs and things like military readiness, effectiveness, lethality, unit cohesion, etcetera,” said the official, who spoke on the condition of anonymity to discuss the details of the policy. “He’s going to continue to ensure that the rights of the LGBT community, as well as all Americans, are protected.”

Democrats and civil rights groups heavily criticized the announcement, calling it a step backward.

“The Commander-in-Chief is ordering the Pentagon to hurt and humiliate thousands of Americans who serve in our military with strength and courage,” House Minority Leader Nancy Pelosi (D-Calif.) said in a statement. “Prejudice, not the national defense, is behind President Trump’s cruel decision to kick transgender troops out of the military.”

The prohibition on funding sex-reassignment surgeries will also go into effect on March 23, 2018, with an exception for individuals currently undergoing the procedures.

Trump’s decision thrust his administration into a contentious debate about rapidly changing norms around sexual orientation and gender identity. The ban on transgender service members was the last such prohibition to be removed after the “don’t ask, don’t tell” policy toward openly gay and lesbian service members was repealed in 2010.

Trump’s decision was made, in part, because of strenuous lobbying from conservative members of Congress who had threatened to hold up a spending bill with money allocated for a border wall — a key policy priority for the president — if the military was allowed to pay for sex-reassignment surgeries. 

While Trump addressed that issue, he also made far more sweeping changes to the military’s policy toward transgender individuals, surprising many in his own party and even advocates who opposed allowing transgender people to serve.

Trump’s announcement was followed by no action for weeks, and his short-circuiting of the policymaking process on the issue caught military officials by surprise.

Pentagon spokeswoman Dana White acknowledged Friday that the Defense Department had received Trump’s memorandum.

“More information will be forthcoming,” White said.