US President Donald Trump on Friday directed [presidential memorandum] JSecretary of Defense ames Mattis [official website] to ban transgender troops from serving in the military if they require surgery or significant medical treatment.

The memorandum revokes the president’s August order [JURIST report], which reinstated a pre-2016 blanket ban on transgender military service but has been challenged in, and blocked by [JURIST report], federal courts as a likely violation of Fifth Amendment [background, PDF] due process and equal protection rights.

The memo affords some latitude to Mattis and other executive officials implementing the policy, and states that:

Among other things, the policies set forth by the Secretary of Defense [Defense Department Memorandum, PDF] state that transgender persons with a history or diagnosis of gender dysphoria—individuals who the policies state may require substantial medical treatment, including medications and surgery—are disqualified from military service except under certain limited circumstances.

In a subsequently released press statement [text], the Trump administration claimed that the policy was:

developed through extensive study by senior uniformed and civilian leaders, including combat veterans…[which] sets forth a policy to enhance our military’s readiness, lethality, and effectiveness. On the advice of these experts, the Secretary of Defense and the Secretary of Homeland Security have concluded that the accession or retention of individuals with a history or diagnosis of gender dysphoria—those who may require substantial medical treatment, including through medical drugs or surgery—presents considerable risk to military effectiveness and lethality. This new policy will enable the military to apply well-established mental and physical health standards—including those regarding the use of medical drugs—equally to all individuals who want to join and fight for the best military force the world has ever seen.

Friday’s order does not alter the federal court injunctions placed against the original ban, which the military will continue to observe, as the cases will likely work their way up to the Supreme Court.