A year ago, President Donald Trump fired off a surprise tweet ordering the Pentagon to ban transgender troops, but the fate of that decision remains in doubt.

Transgender troops so far have remained in uniform as lawsuits on the issue grind through the courts.

The Pentagon, which took months to study the transgender ban, released guidelines in February that banned those who have undergone gender reassignment therapy. But the ban didn’t cover all transgender troops, and even the limited restrictions are being litigated.

“Among other things, the policies set forth by the secretary of defense 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,” Trump said in a March memo on the new policy.

The attempted reversal of the Obama-era policy that allowed transgender military service is an odd shift for a governmental entity that long has led the nation in civil rights reforms.

During World War II, the military allowed black pilots to earn their wings in what was seen as a major blow to Jim Crow policies. The Tuskegee Airmen’s success led to a 1948 decision that ended racial discrimination in the Defense Department.

In the 1970s, the military became a leader in the women’s rights movement. The first women were allowed entry into the nation’s service academies in 1976.

In the 1990s, the Pentagon adopted a policy of “don’t ask, don’t tell,” the first step toward allowing gays and lesbians to serve. In 2010, the Pentagon ended restrictions tied to homosexuality.

In 2016, the Pentagon approved transgender service and changed policies to allow women to serve in combat roles that had been male-only.

Transgender rights groups have filed suit against Trump, seeking to block the new ban. Court rulings in the matter could come later this summer.