One Candidate Rose to the Occasion. Guess Which.

C'mon. Guess.

Photographer: Andrew Harrer/Bloomberg

There are two major-party candidates for president of the United States. Any undecided voter (yes, they still exist) who watched the first presidential debate on Monday could plainly see that only one of them came prepared.

Hillary Clinton showed the expertise and judgment that she has displayed -- with notable exceptions -- for more than four decades. She generally responded to the questions asked with arguments that were logical and coherent.

Such a performance should be routine in a presidential debate. No one was surprised, for example, when Mitt Romney and Barack Obama both proved to be articulate and respectful four years ago. But this is not a normal election.

In last night’s debate, as in other matters, Donald Trump showed he has no interest in the usual way of doing things. With rambling and often factually incorrect responses, dozens of interruptions of his opponent and the moderator, and an alarmingly loose grasp of public policy, he turned the debate into a demolition derby of reason. Asked to respond to charges made by his opponent, he simply denied saying things he had in fact said. Given the chance to talk about substantive issues -- say, race relations or home-grown terrorism -- he offered few insights or specifics.

A debate is a high-pressure experience, intellectually and emotionally demanding. But so is the presidency. If Trump cannot prepare for a 90-minute exchange -- and show some competence, coherence and decorum -- it’s hard to see how he can rise to the complex tasks of running the most powerful nation on earth.

To contact the senior editor responsible for Bloomberg View’s editorials: David Shipley at davidshipley@bloomberg.net.