From the beginning, people around me talked nonstop about the end.

How long could Donald Trump’s presidency possibly last? Would impeachment or the 25th Amendment undo him? Before Trump, few of us even knew of the 25th Amendment, which allows the vice president and a majority of the cabinet to decree the president unfit. But suddenly everybody was up to speed, and no sooner had Trump been inaugurated than the “would you rather” question du jour became him versus Mike Pence. All-purpose lunacy or religious zeal: Choose your governance. Pick your poison.

Part of this, yes, reflected the company I keep. It doesn’t brim with Trump enthusiasts. But more of this came down to Trump himself — the lidless grandiosity, the bottomless vulgarity, the lies atop lies upon lies. I’ll never forget his second day in office, not just because he used an appearance at the C.I.A. to crow at great length about his many Time magazine covers and to insist, despite ready evidence to the contrary, that any beef of his with intelligence agencies was a media invention. It stays with me because of a text message I received from a journalist who covers him as well as any other, understands him better and was utterly flabbergasted by that display.

“We’re all going to die,” it said. While there was jest and hyperbole in that, there was also genuine alarm and the dark realization that Trump would not be transmogrified by the oath of office into anything approaching a dignified, responsible statesman. No, his extra power was just making him extra mean, and what we saw before Nov. 8 was what we got from Jan. 20 onward: a child in a man’s suit, a knave in a knight’s armor, a dangerous experiment with unforeseeable consequences.

They’re more seeable now. As of Thursday, July 20, Trump will have inhabited the presidency for a full six months, and we can reach certain conclusions with a measure of confidence.