Buttigieg was the first major openly gay presidential candidate, and he challenged and changed Americans’ preconceptions of what such a candidacy would look like, as I wrote in a column just before the Iowa caucuses. One of the wonders of his unprecedented campaign was how little his sexual orientation was talked about as his bid progressed. That spoke to the range of political talents he brought to the contest and the breadth of the issues he engaged. He was a novelty who resisted being just that, a symbol who wouldn’t be content with mere symbolism.

Rush Limbaugh, to whom Trump awarded the Presidential Medal of Freedom in January, was more deviation than norm when he gawked at the hypothetical scenario of Buttigieg, as the Democratic nominee, “kissing his husband onstage next to Mr. Man Donald Trump.” Mr. Man? In a Buttigieg-Trump face-off, only one face would glow oddly orange, and only one head of hair would appear to be the work of a dozen tipsy sprites.

Of course Buttigieg, ever dexterous, had the perfect retort when asked about Limbaugh’s ugliness during a CNN town hall. “The idea of the likes of Rush Limbaugh or Donald Trump lecturing anybody on family values, I mean, sorry, but one thing about my marriage is it’s never involved me having to send hush money to a porn star after cheating on my spouse,” he said. “They want to debate family values, let’s debate family values. I’m ready.” Was he ever.

While some of his critics on the left conducted an offensive discussion about whether he was gay enough, he performed an important balancing act, integrating his gayness into his candidacy without letting his candidacy be defined by it, seizing teachable moments without ever becoming tendentious or tedious, showing the world that being gay or lesbian or bisexual or transgender or queer is an essential part of who we L.G.B.T.Q. people are but not all of who we are.

On Sunday night in South Bend, where he delivered a poignant valediction to his campaign before hundreds of cheering supporters, he noted that it had “sent a message to every kid out there wondering if whatever marks them out as different means they are somehow destined to be less than.” They could look at him, he added, “and see that someone who once felt that exact same way can become a leading American presidential candidate with his husband at his side.”

He was talking about the experience of being in a minority and being marginalized — about the sorrow and the fear — and one of the great disappointments of his candidacy was his inability to build a bridge between himself and others who have had that experience. He was getting better and better at it, though. He was ever more attentive to that crucial task — in his last debate, for example, and in his speech on Sunday night.

I listened to it and realized that what most impresses me about him isn’t his intellect per se — the fancy degrees he has, all the languages he speaks — or his crazy poise or the manner in which he handled the unconventional aspects of his candidacy.