The September 11, 2001, terrorist attacks struck an unprepared America mere months into President George W. Bush’s first term. Nothing in his tenure to that point was particularly memorable. Nothing he had ever faced in life was remotely comparable. And the United States was forever shaped by the strengths and weaknesses exhibited by the Bush administration as its officials decided how to respond.

For the couple of weeks preceding the anniversary of 9/11, I’ve been fretting about what would happen if Donald Trump, who has reached the same point in his first term, is still president if and when this country next faces a challenge as significant. As a staunch, longtime critic of both Presidents Bush and Obama, I am under no illusion about the costly consequences of their warmaking in Afghanistan, Pakistan, Iraq, Libya, and Yemen, the dangers posed by their civil-liberties abrogations, or the abuses they perpetrated and courted with mass domestic surveillance.

Even so, I do not think that the United States has ever elected anyone less suited than Trump to lead it through a major terrorist attack, a war, or a challenge of similar scale.

I don’t merely mean that President Trump has no governing experience, though he does not; or that his past bankruptcies make one wonder what Taj Mahal Casino-like ruins are in his future; or that I think poorly of his moral compass and his ability to master himself, though I find him unfit to lead in a nuclear age based on those traits alone.