July 26 is a significant day in American military history. Sixty-nine years ago, on July 26, 1948, President Harry Truman signed an executive order abolishing racial segregation in the Armed Forces allowing African-Americans to serve in all branches of the military.

Fast-forward. July 26, 2017 will go down in military history for a different reason. On that day, President Donald Trump sent out a tweet bringing discrimination back to the Armed Forces by banning all transgender troops from military service.

In an early morning tweet that blindsided members of Congress, White House staffers, and the Secretary of Defense, Trump declared that, effective immediately, transgender Americans would not be allowed to serve “in any capacity in the U.S. military.” Why? Because, Trump argued, the military “cannot be burdened with the tremendous medical costs and disruption that transgender in the military would entail.”

Note the key word: “disruption.” Sound familiar? It should. Because it’s the exact term previously used to deny blacks, women, and gays the right to serve in the military. It was phony then, and it’s phony now.

Truman shot down that argument in relation to African-Americans. But in the 1990’s it was back, aimed against women by men who argued either that women didn’t belong in the military at all because they’d be too big of a distraction for male soldiers.

Ironically, President Bill Clinton resolved the women-in-combat issue, only to fall for the phony argument that gays shouldn’t be allowed to serve openly in the military, either. Having gay and straight soldiers serve side by side meant “the introduction of sexual attraction,” one general warned Congress, and “could lead to combat deaths.”

It took President Obama to end “Don’t Ask, Don’t Tell” and to roll out the welcome mat for transgender Americans — a policy now reversed by Donald Trump, who would not allow them to serve “in any capacity.”

Donald Trump’s hissy fit has no basis in fact. Take the numbers. In 1948, writes the New York Times, “…there were about 62,000 black soldiers in the Army … about a tenth of the total.” Today, “there are between 1,000 and 7,000 transgender service members on active duty, of 1.3 million in total.” That’s hardly enough to undermine military readiness.

Most important, those transgender soldiers are serving our country with valor and distinction around the globe. What happens to those brave transgender now in uniform?

As for the “tremendous medical costs” involved, that’s a phony argument, too. As Politico first reported, that’s what triggered the surprise Trump tweet. Conservative House Republicans initially tried to amend the defense appropriations bill by blocking the military from paying for surgery or hormone therapy for transgender soldiers. Based on a 2016 Rand Corp. study that found trans-related medical care only amounts to $2.4 to $8.4 million, or 0.004 to 0.17 percent of the overall $49.3 billion Pentagon health care budget, 24 Republicans joined 190 Democrats in voting against that amendment.

Freedom Caucus Chairman Mark Meadows then warned the White House that, without this provision, conservatives would kill the entire defense bill, which — guess what? — includes money for Donald Trump’s pet project, the border wall. Whereupon, in order to save his sacred wall, Trump decided to throw transgender Americans under the bus: not only by refusing to pay their health care, which is all conservatives wanted, but by banning them from the military altogether.

And, of course, he did so in the middle of what the White House was calling “American Heroes Week.”