Given the president’s delusions, the strangest part of his prime-time address on Tuesday night didn’t turn out to be a declaration of national emergency or a breathtakingly vulgar denunciation of undocumented immigrants. It was the sight of Trump straining to play a normal president. The performance didn’t last long. And it suggested that if Trump suddenly acquired the self-discipline to behave the way we expect a president to act, the resulting whiplash might be even more jarring than the past two years have already been....

Those very gestures of presidential normalcy revealed how futile it was for anyone to wish that Trump would start talking like that all the time. Trump may have told more blatant falsehoods about immigrants and crime over the course of his speech, but to watch him mouth these platitudes is to witness a more insidious and disorienting kind of lying....

Watching Trump’s flat delivery of sentiments that he can’t possibly believe was the inverse of comforting. Instead, the address had the queasy effect of a serial killer’s mask in a horror movie: It was a failed attempt to look normal that concealed something even more terrifying underneath.

In the second half of the address, that mask dropped away and Trump regained some of his animation as he described terrible crimes committed by undocumented immigrants. The whole performance is a testament to why it’s unwise to hope that Trump grows into his office and that he learns how to play a normal president. If he did, he’d be much more effective at advancing his agenda, and people on both sides of the border would be in much greater peril.