Donald J. Trump once said his enrollment in a military high school was equivalent to serving in the actual military.

He was wrong. What’s the president doing now? He has decided to attack at least two actual veterans who now serve in the U.S. Senate.

A word of advice, Mr. President: Do not go there.

First case: Sen. Richard Blumenthal, D-Conn., reported that Supreme Court nominee Neil Gorsuch called Trump’s tweets criticizing federal judges “demoralizing” and “destabilizing.”

Trump’s reaction was to call attention to Blumenthal’s assertion years ago that he once served in the Vietnam War. Blumenthal didn’t go to Vietnam. However, the senator did serve in the military.

Next case: U.S. Sen. John McCain, R-Ariz., criticized a military mission that Trump ordered that resulted in the loss of an expensive aircraft and the life of a Navy SEAL.

Trump’s press flack said McCain dishonored the memory of the slain SEAL.

Trump treads on tricky ground.

Remember, too, that candidate Trump once said McCain was a Vietnam War hero only because “he was captured. I like people who aren’t captured, OK?” I’ve spoken my piece already on that shameful and ridiculous assertion.

But as a veteran of the Army myself — who served for a time in Vietnam — I take tremendous umbrage at the president going after veterans when he has no knowledge of what they endured.

In the case of McCain in particular, I would caution Trump strongly to avoid launching anything resembling a personal attack on this gallant war hero.