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, and look how poorly the U.S. has done, Trump wrote on Twitter.