WASHINGTON — The Trump administration urged the U.S. Supreme Court Friday to immediately take up the legal battle over transgender military service, asking the justices to act even before the issue has gone through the lower courts.

The Supreme Court rarely allows such a move to leapfrog over the usual appeals process, but Solicitor General Noel Francisco said the Obama administration's policy of allowing transgender service poses a threat to military readiness and imposes "an unreasonable burden on the military that is not conducive to military readiness and lethality."

President Donald Trump took the Pentagon by surprise in July 2017 when he said in a series of tweets that the government "will not accept or allow" transgender individuals to serve in any capacity in the U.S. military. Six months later, Defense Secretary James Mattis proposed a modified policy, ultimately approved by the president, that would allow transgender individuals to serve, but only if they did not seek gender transition and agreed to serve "in their biological sex."

The revised plan reversed the policy imposed during the Obama administration, allowing transgender members to serve openly and even to receive sex reassignment surgery. But the Pentagon hoped the Mattis order could prevail against the expected discrimination lawsuits by saying that it was not based merely on status.

The Mattis policy was immediately challenged, and four federal courts issued orders forbidding the government to enforce it. Federal District Court Judge Marsha Pechman of Seattle said that "discrimination against transgender people clearly is unrelated to their ability to perform and contribute to society." Other judges said the policy was nothing more than a plan to carry out the outright ban on transgender service announced by President Trump.

In urging the Supreme Court to take the case now, the Justice Department said allowing the Obama transgender military service policy to continue would undermine military readiness and unit cohesion. Allowing service members "who retained the anatomy of their biological sex to use the facilities of the preferred gender” would invade the privacy of others. And permitting a biological male who identifies as female to compete against women in training "would pose a serious safety risk and generate perceptions of unfairness."

Civil liberties groups condemned Friday's move by the government.

"It seems the Trump administration can't wait to discriminate," said Peter Renn of Lambda Legal. "There is no valid reason to jump the line now and seek U.S. Supreme Court review before the appellate courts have even ruled on the preliminary issues before them."

Sarah McBride of the Human Rights Campaign said the Trump administration was rushing the process "because they know that every day that transgender people continue to enlist and serve with distinction is another day that the courts and the public see this irrational policy for what it is."

The Supreme Court has agreed only about a dozen times in the past century to take a case so quickly and bypass the federal appeals courts, usually involving a national emergency such as nationwide strikes in the steel and coal industries.

In Friday's filing, the Justice Department said the court has done so in the past "to promptly resolve important and time sensitive disputes," but offered only three examples in the past 66 years.