ON the morning of the second presidential debate, Marco Rubio gave a performance every bit as riveting as the ones the candidates turned in less than 12 hours later.

He was visiting Bloomberg View in Manhattan, where he sat down with political journalists for a freewheeling hourlong conversation. I’d never met him and was eager to, given the belief of many Republicans that he has a big future in the party, and in politics.

I was impressed first and foremost by the assurance with which he spoke, projecting a wisdom and an authority beyond his 41 years.

But I was even more struck by something else: the dispiriting, infuriating way in which he deployed that assurance and what that said about our sorry politics today. Instead of conducting a blunt, honest examination of the hard choices and necessary compromises that confront our country, he presented the sorts of rosy assumptions and slippery generalizations that have characterized too much of this election.