In the eight-plus months that we've been living under the Trump presidency, one harrowing question has been hovering just slightly above all the news cycle-dominating drama of an incompetent president bungling his way through the world's most important job: What happens when there's a real crisis?

Up to this point, the crises and failures of Trump and his administration have been largely political and self-made. But then a series of hurricanes blew through the Atlantic Ocean and the Gulf of Mexico, wreaking devastation on several U.S. states and territories. Puerto Rico and the U.S. Virgin Islands were pounded by hurricanes Irma and Maria, leaving the islands in ruins and the approximately 3.5 million American citizens who live there in desperate straits, with no power, water, or communications.

And as two U.S. territories suffer from natural disaster, a man-made catastrophe looms ever larger, as the government of North Korea ramps up its bellicose rhetoric while test-firing rockets that it claims can be used to conduct nuclear strikes on the U.S. and its allies.

These are the crises that everyone feared were coming. The president who showed up to handle them is, lamentably, predictably, the same bumbling and pathologically ego-driven lout from the last eight months. His behavior over the past weekend when facing down these crises was appalling in every sense.

Criticism of the speed of the federal response to the disaster in Puerto Rico came to a head on Friday when San Juan Mayor Carmen Yulín Cruz issued a televised plea for help. "People are dying in this country," she said. "If anybody out there is listening to us, we are dying and you are killing us with the inefficiency and the bureaucracy."

This clearly stung Trump, who has been offering a relentlessly upbeat assessment of the havoc in Puerto Rico and wasn't about to let some local politician — a Latina woman, no less — contradict him. In a series of tweets attacking the mayor of an American city flattened by a monstrous storm, the president called Cruz a poor leader, a tool of the Democrats, a complainer, and a "politically motivated ingrate."

Still worse than that was his despicable assertion that disaster-stricken Puerto Ricans "want everything to be done for them when it should be a community effort." The story out of Puerto Rico has been the degree to which communities have pulled together what meager resources remain to help each other in the absence of government aid. Trump dismissively brushed off that heroism born of misery and instead cast the island's population as ungrateful layabouts waiting on a handout. It was among the more disgraceful demonstrations of presidential behavior, combining healthy doses of racial condescension and absurd egotism.

Not long after he was through denigrating the storm-ravaged citizens of his own country, Trump switched gears and decided to humiliate his own top diplomat. On Saturday, Secretary of State Rex Tillerson confirmed that the U.S. had opened direct lines of communication with North Korea as a means of ratcheting down the nuclear-backed tension between the two nations. Trump, however, once again popped off via Twitter. "I told Rex Tillerson, our wonderful Secretary of State, that he is wasting his time trying to negotiate with Little Rocket Man," Trump wrote, using the silly nickname he devised for Kim Jong Un. "Save your energy Rex, we'll do what has to be done," he added.

These tweets were insane, and not just because of the implied threat of war, which has become a dangerously commonplace feature of Trump's North Korea rhetoric. The president of the United States denigrated the diplomatic work of his secretary of state, gave him a condescending "well, at least you tried," and told him to step aside so that the important people could do whatever it is that needs doing. Why on Earth would any world leader give any credence to anything Tillerson has to say when the president publicly treats him like a hapless dolt and countermands his policies via tweet?

All of the self-sabotaging insanity that emerged from the president over the past few days was delivered via Twitter. This weekend stands out as one of the clearest demonstrations yet of just how destabilizing and dangerous it is that Trump has this means of broadcasting directly to the world the poison and madness that infects his brain. Crises like the devastation in Puerto Rico and the tensions with North Korea require careful thought and considered action. Trump is capable of neither, and we'll be very lucky if the president's incurable urge to tweet whatever foolish thing rattles through his mind doesn't end up getting people killed.