Contributing columnist

Out of the blue, with no new data and the same team of generals, President Trump has decided that he wants to reinstate the ban on transgender people in the military, reversing Obama administration regulations allowing all men and women, regardless of gender identity, to serve their country.

This is the same man who, when running for office, claimed to be a friend of the LGBT community. Perhaps he’s forgotten that the “T” stands for “transgender.”

Make no mistake, the president’s anti-transgender offensive is an attack on the entire LGBT community and on our core American belief in equality of opportunity.

The commander in chief’s ­early-morning tweets on Wednesday calling for reinstatement of the ban laid out a bogus argument, leaving out the most important point: This is a political move intended to appease Trump’s base and to push Democrats “to take complete ownership of this issue,” according to an unidentified Trump administration official quoted by Jonathan Swan, a national political reporter for Axios.

Here’s what the president had to say:

“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. 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. Thank you.”

Who are these generals and military experts? I posed that question to Matt Thorn, executive director of OutServe-SLDN, an organization that represents the LGBT community in the military. “Your guess is as good as mine,” he said. Thorn pointed out that the current service chiefs signed off on the Obama policy last year and that “those individuals haven’t changed. There have been no replacements.”

He also reminded me that it was a 2016 study by the Rand Corporation (commissioned by the Pentagon) that led Obama defense secretary Ashton B. Carter to lift the ban. No new study has been conducted or published since then, meaning that there’s no new data.

What’s also deeply unsettling, to say the least, is that Trump tweeted this intended policy change only a few weeks after Defense Secretary Jim Mattis gave military chiefs a six-month extension, until Dec. 1, to determine whether transgender service members would affect the military’s “readiness and lethality.” Is Trump undermining yet another of his Cabinet members? Curiously, Mattis is apparently on vacation, according to numerous news reports. If you’re going to consult your experts, shouldn’t the defense secretary be one of the top voices in such an important and far-reaching decision?

As for the “tremendous medical costs” that would result if transgender people were allowed to continue serving, the Rand study is the gold standard on that question as well. The think tank estimated that between 30 and 140 new hormone treatments a year could result, as well as 25 to 130 gender-transition-related surgeries. The estimated impact on the military’s health-care costs would fall between $2.4 million and $8.4 million, or a tiny bump of 0.13 percent, which is hardly “tremendous.” (And that’s for all medical costs, not just transition-related ones.)

What about the “disruption” supposedly caused by allowing openly transgender men and women to serve? There’s no there there. “Service members have been serving openly with no issues to readiness,” Thorn said. “They’re serving in elite units, like SEAL Team 6 [and] in the Joint Chiefs of Staff office. They’re leading commands and leading battalions. It’s not true.”

The same claims were made of gay and lesbian service members during the “don’t ask, don’t tell” era; it’s fearmongering, plain and simple.

With no rationale, and no new data or studies, the president has thrown the LGBT community — and notably transgender people — under the bus. Conservative groups such as the Family Research Council, long apposed to LGBT equality, applauded the president’s move, especially his termination of what they called a “social experiment.” It’s an interesting footnote that on the same date in 1948, President Harry S. Truman issued Executive Order 9981, which abolished racial discrimination in the military. He called for “equality of treatment and opportunity in the military.”

My question for President Trump: Why does that same principle not apply to transgender Americans who want to serve their country?