When James Mattis resigned in protest from Donald Trump’s cabinet, it was the moment every Trump opponent knew would happen and every Trump supporter feared. With Mattis’s looming exit, Americans confront two deeply unsettling realities.

First, the chaos that finally cemented Mattis’s decision to leave — including the president’s snap decision to abandon the Middle East to the Russians and the Iranians — confirms the worst fears of Trump’s most dire critics. Trump’s defenders have always tried to maintain that behind the scenes, there were tough, principled people — like, say, James Mattis — to whom Trump, for all his bluster, would listen. The damaging stories tumbling out of the White House, they shrieked, were just fake news, planted by Trump’s enemies in the left-leaning media.

Mattis’s resignation, however, suggests not only that the terrifying accounts in books like Bob Woodward’s "Fear" are true, but that the reality is worse than we know. (Mattis, Woodward claims, tried to explain to Trump how U.S. alliance commitments are designed to prevent World War III, only to find, as Mattis is quoted as saying, that Trump has the intellectual capacity of a grade-schooler.) No Secretary of Defense has ever resigned in public protest; Mattis, a man with a deep sense of history, knows this, and therefore knew the gravity of his decision. And so we must assume the worst about the utter meltdown inside the White House.

Likewise, there can be no more pretense that the president cares what his advisers think, or that the next occupants of these positions will matter any more than their predecessors did. At this point, the president seems interested in the advice of his advisers only so that he can do the opposite of whatever it is. As prominent Trump critic Rick Wilson has often repeated: There is no better Trump.

If anything, Mattis’s resignation suggests not only that there is no better Trump, but that the one we have is getting worse by the day. ...