Updated Jan. 23 at 11 a.m. ET

The Supreme Court has reinstated President Trump's order placing restrictions on transgender persons enlisting and serving in the military by granting a stay of two lower court injunctions that had blocked the president's policy. The justices voted 5-4, reflecting the high court's conservative majority.

The decision allows the Pentagon to prevent many transgender persons from joining or, in some circumstances, remaining in the military while the lower court rulings that had blocked the policy are appealed. The justices did not allow the Trump administration to leapfrog the appeals court, as it had requested.

In a statement Wednesday morning, the Pentagon said a fourth national injunction from a case in Maryland U.S. District Court remains in effect. The statement said the Department of Justice is seeking to lift that injunction as well "in light of the Supreme Court's action." Until that happens, the transgender policy will not be implemented.

The two cases before the Supreme Court — Trump v. Karnoski and Trump v. Stockman — are currently working their way through the U.S. Court of Appeals for the 9th Circuit.

In both of those cases, Justices Ruth Bader Ginsburg, Stephen Breyer, Sonia Sotomayor and Elena Kagan would have maintained a stay on the ban, Tuesday's Supreme Court order reads.

The transgender ban is being revived more than a year after a federal court in Washington, D.C., first blocked it in October 2017. U.S. District Judge Colleen Kollar-Kotelly ruled that trans members of the military had "a strong case that the president's ban would violate their Fifth Amendment rights," as NPR reported.

A three-judge panel of the U.S. Court of Appeals for the District of Columbia Circuit lifted Kollar-Kotelly's injunction earlier this month, concluding that the ban had been substantially revised by the time it was instituted by former Defense Secretary Jim Mattis in March 2018. But other federal courts had also ruled against the ban — and until Tuesday, those other injunctions remained in place.

The two outstanding cases come from California and Washington state, in the 9th Circuit's jurisdiction.

Pentagon rules

Under Trump's policy, transgender persons who have a history or diagnosis of gender dysphoria and who may require "substantial medical treatment, including medications and surgery" are, with some exceptions, disqualified from military service.

The exceptions fall into four categories:

1. The more than 900 active-duty members of the military who a Pentagon report says were diagnosed with gender dysphoria after June 30, 2016. On that date former Defense Secretary Ash Carter lifted a prior ban on transgender persons serving in the military. This group will be allowed to receive required medical treatment to transition and to serve in their preferred gender, as long as they are not deemed nondeployable for more than 12 months.

2. Those who have been "stable for 36 consecutive months in their biological sex" before entering the military.

3. Those who have been diagnosed with gender dysphoria after beginning their military service but "do not require a change of gender."

4. Those whom the Pentagon calls "transgender persons without a history or diagnosis of gender dysphoria" and who serve "in their biological sex."

Disqualified from serving in the military, according to a February 2018 memo from Mattis, are "transgender persons who require or have undergone gender transition." Mattis based his recommendations on a 2017 study he had ordered, in which a 2016 Defense Department survey estimates that about 1 percent of the active-duty force, or 8,980 service members, identify as transgender.

Stark contrast between two administrations

The Human Rights Campaign, which is involved in the Karnoski case in Washington state, condemned the Supreme Court's decision, saying it "thrusts this administration's discriminatory agenda onto a military that clearly doesn't want it, and does so at the expense of transgender people's careers and service."

Trump announced his ban abruptly in the summer of 2017, saying in a series of tweets that "the United States Government will not accept or allow...... ....Transgender individuals to serve in any capacity in the U.S. Military."

The decision seemed to take Defense Department officials by surprise, sparking confusion despite Trump's assertion that he had consulted "with my Generals and military experts."

The tweets were followed by an official presidential memo in August of that year, which gave the defense secretary (and for the Coast Guard, the homeland security secretary) the discretion to "determine how to address transgender individuals currently serving in the United States military."

Trump's ban was a sharp reversal of a Pentagon policy announced in June 2016, when Carter said, "Effective immediately, transgender Americans may serve openly, and they can no longer be discharged or otherwise separated from the military just for being transgender."

That Obama-era policy was hailed as ending an era of legal and professional limbo for transgender persons in the U.S. armed services; Carter said the decision was made out of a desire to attract "all talent possible" to serve in the military.

At the time, researchers at the Rand Corp. think tank estimated there were as many as 7,000 active-duty transgender service members, with up to 4,000 more in the reserves.

Because of that policy and the lower court injunctions, the first openly transgender persons were able to join the U.S. military on Jan. 1, 2018. But now their status is once again in jeopardy.

Tuesday's order states that restrictions on transgender persons in the military will remain in effect until the 9th Circuit rules on the policy. The stay would continue if the case is argued before the Supreme Court.

NPR's Domenico Montanaro contributed to this report.

Copyright 2021 NPR. To see more, visit https://www.npr.org.