It’s the first rule of crisis communications: When you’re in the hole, the first thing you do is to stop digging.

But if you’re President Donald Trump, you equip yourself with a hardhat with a miner’s light, reflective gear, heavy-duty gloves, and fire up Mary Anne, the reliable steam shovel from “Mike Mulligan and His Steam Shovel,” and commence digging even deeper.

In the past week, Trump has plumbed new depths of indignity, visiting fresh humiliations on his already degraded office, by picking a fight with a pregnant war widow and accusing her of lying; escalating his feud with U.S. Sen. Bob Corker of Tennessee, and issuing a stern warning to U.S. Sen. John McCain that the Arizona Republican should “be careful, because at some point I fight back.”

Trump, who has a glancing relationship with the truth and speaks English only as a second language, has hurled his insults at Corker (whom he said couldn’t get elected dog-catcher in his home state) and at McCain — even as he journeyed to Capitol Hill to try to build support for tax reform.

In case Trump has forgotten, he needs every Republican vote — including Corker’s and McCain’s — if he hopes to win passage of his deficit-exploding tax plan.

Trump only damaged himself when he attacked “liddle” Corker on Twitter,falsely accusing him of working with former President Barack Obama to “give us the bad Iran deal.” He also dismissed Corker as the “incompetent head of the [Senate] Foreign Relations Committee.”

As The Washington Post reported, Corker not only voted against the Iran deal, he also marshaled legislative support against it. And as chairman of the Foreign Relations Committee, Corker has the power to bottle up the administration’s pick for Secretary of State, in the event that current chief diplomat Rex Tillerson finally reaches a tipping point and decides to quit.

So logic would appear to dictate that Trump try to work past those differences and cultivate Corker’s support.

But this is Donald Trump’s Washington, where logic has hung a “Back in 2020” sign on its office door and headed out for an extended holiday — perhaps to some far-flung island with non-existent broadband service.

“Sen. Corker is the incompetent head of the Foreign Relations Committee, & look how poorly the U.S. has done, Trump wrote on Twitter. “He doesn’t have a clue as the entire World WAS laughing and taking advantage of us. People like liddle’ Bob Corker have set the U.S. way back. Now we move forward!”

True, Corker probably didn’t help matters by reinforcing his view to “Good Morning America,” that the White House is an adult daycare center, later slamming the “same untruths from an utterly untruthful president.”

The ongoing war of words between Trump, Corker and McCain — however destructive and uncivil — could be reasonably dismissed as mere posturing between some towering male egos.

But Trump’s needless fight with Myeshia Johnson, the widow of one of four Army soldiers killed in operations in the African nation of Niger, proves the case that spats with Corker and other political enemies stem from deeper flaws in the president’s character.

Trump at first accused a Florida congresswoman listening in on speakerphone of distorting the content of his call to Johnson. That account was later seemingly confirmed by Trump’s chief of staff, former Marine Gen. John Kelly.

Not satisfied with the damage inflicted there, Trump lashed out on Twitter after Johnson told “Good Morning America” that she was unhappy with the tone of Trump’s bobbled attempt at a condolence call and complained that the president could not remember her husband’s name.

“I had a very respectful conversation with the widow of Sgt. La David Johnson, and spoke his name from beginning, without hesitation!” Trump wrote, needlessly heaping more trauma on a grieving family.

A bigger man would have let that slide.

An empathetic commander-in-chief, burdened by the responsibility of sending men and women possibly to their deaths in combat, would have silently absorbed the barbs, recognizing them as coming from someone dealing with incomprehensible loss.

But Donald Trump?

He just keeps digging.

An award-winning political journalist, Micek is the Opinion Editor and Political Columnist for PennLive/The Patriot-News in Harrisburg, Pa. Readers may follow him on Twitter @ByJohnLMicek and email him at jmicek@pennlive.com.