Leaving the Trump White House on happy terms is like dying a peaceful death in the wild—possible but exceptional. Lingering torment is the norm. Erstwhile Department of Homeland Security Secretary Kirstjen Nielsen, who has been dismissed, was already out of favor a year ago, and Donald Trump had for months been signaling his intention to replace her. He was angry Nielsen didn’t seem to be coming up with inventive work-arounds for the law (like breaking it), and last October he spent about half an hour berating her during a Cabinet meeting.

It’s all very Trumpy. If a job on the farm calls for a border collie, you don’t buy a dachshund. If the church needs a priest, you don’t hire an atheist. But Trump does. He hires people who don’t share his agenda and then gets furious at them for being what they are. Kirstjen Nielsen had minimal management experience and didn’t share his worldview. Nor was she prepared to block every border violator from claiming asylum, a response that would have meant ordering an entire bureaucracy to ignore the law. Her executive-branch work had been for the administration of George W. Bush, and any hawkishness on the border was dutiful rather than heartfelt. This wasn’t her fault.

Trump likes to blame others for his incompetence. One can read claims that he was angry to discover that an omnibus spending bill he had signed included minimal wall funding, as if Trump didn’t know that when he signed it. When Trump proposed impossible or impractical policies for addressing a wave of asylum-seeking migrants, like shutting down the border altogether, Nielsen had the unhappy job of explaining the law to him. To be sure, a more dynamic and hard-line leader than Nielsen might have thought of creative alternative ways to stem the flow, but it took someone as bumbling as Trump to pass the buck to D.H.S., like a team that provides no defense and then yells at the goalie when the other side scores.

The border crossings are a genuine mess that Congress has helped to create. They involve arcane laws and regulations such as the “Flores settlement” and the “credible fear” test. But the bottom line is that if you cross the U.S. border with a child in tow and request asylum, you get to enter the country and stay indefinitely. (That’s provided you’re not Canadian or Mexican, because of aforementioned arcane laws.) This has caused a rate of influx that, if D.H.S. is to be believed, is approaching a million people per year. It has also incentivized people to bring children on dangerous journeys overseen by organized crime in Mexico.

If Trump really cared about this problem, he could have prioritized plugging the loopholes and hiring enough immigration judges to process the asylum claims in weeks rather than years. He did, after all, have Republican majorities in the House and Senate for two years. When it came to pushing Congress for legislation, though, Trump synced up with the establishment Republicans and pushed for tax cuts and the torpedoing of Obamacare, either in order to be protected from Democrats as investigations were brewing or else to make things easy for himself with the home team. Nothing on the border got fixed.

To be sure, Trump wouldn’t be the first president who didn’t care about policy details or hated studying up on anything. But being ignorant of specifics means that you must hire very, very well, because you are putting yourself at the mercy of advisers and personnel when it comes to making decisions and trusting them to share your aims. Trump can’t be bothered to look for those people, either.