President Harry S. Truman. Getty Images

President Donald Trump tweeted on Wednesday morning that the US military would not accept transgender people.

But 69 years ago, to the day, President Harry Truman ordered the end of discrimination in the US armed forces as "rapidly as possible," according to The New York Times.

Truman said that men in uniform should have "equality of treatment and opportunity," without regard to race, color, religion, or even national origin.

Further, Truman ordered that "merit and fitness" be the only qualifications for a job in the federal government. The New York Times reported at the time that Truman's orders would have a "thunderbolt effect" on the "highly charged" political situation in the South.

President Barack Obama announced in 2016 that openly transgender people would be allowed to serve in the military, though the implementation of that policy had been delayed by Secretary of Defense Jim Mattis.

Trump's Wednesday morning announcement indicates a reversal of that decision.

Up to 10,700 transgender people may already be serving in the US military, according to a 2016 study by the RAND Corporation. The RAND study estimated that 29 to 129 of the US military's 1.4 million troops would seek reassignment surgery each year.