Jimmy Kimmel deserves credit for frankness, if nothing else. In an interview over the weekend, the ABC late-night host said he doesn’t care about losing Republican viewers.

We’re a long way from Johnny Carson, whose “Tonight Show” was a national institution that enjoyed a broad audience — and was conducted like one. Carson steered clear of politics and kept his views to himself because delving into divisive politics would “hurt me as an entertainer, which is what I am.”

Kimmel may be an entertainer, but he has no such inhibitions. He is willing to say “not good riddance, but riddance,” as he put it in the “CBS Sunday Morning” interview, to Republicans put off by his headline-generating editorials in recent weeks.

Once a down-the-middle comedic voice who co-hosted the unapologetically vulgar “Man Show” on Comedy Central, Kimmel uttered what could be the epigraph for our times, saying of viewers who strongly disagree with his political views, “I probably won’t want to have a conversation with them, anyway.”

From Carson to Kimmel is the story of the fracturing of a media environment that has made niche audiences the coin of the realm. Add on top of this an inflamed anti-Trump resistance cheered on by the elite media, and Kimmel kissing off Republicans is probably a good career move.

His impassioned monologues on health care — originally occasioned by the illness of his little son, Billy — and gun control have won media accolades. A CNN piece even deemed him “America’s conscience.” The press is nice puffery, but what matters to his employer is the ratings, which are notably up.

Stephen Colbert of CBS blazed this particular trail with increasingly over-the-top denunciations of President Trump that vaulted him to the top of the late-night ratings. Jimmy Fallon, the heir to Carson’s “Tonight Show” via Jay Leno, has pointedly declined to make his show the New York Times editorial page with a few jokes attached, and has seen ratings decline.

It is important to note that these shows are competing for numbers that once would have been considered catastrophic. Carson could pull in 9 million viewers when one of his shows popped; he averaged 19 million viewers a night his final week on air in 1992.

Stephen Colbert is winning the late-night race with 3 million viewers. That’s better than MSNBC’s Rachel Maddow, but not by much. This means that all it takes to become a giant of late-night TV is winning over a Maddow-like audience, exactly Colbert’s strategy.

If this trend is inevitable, it’s not a good thing. It removes yet another neutral zone, free of social and political contention, from American life.

It means that the quality of the comedy on these shows probably goes down (agitprop isn’t funny), while the quality of the political commentary is inevitably poor; Jimmy Kimmel’s wholly ill-informed gun monologue subtracted from the nation’s understanding of the issue, as you’d expect of a comedian who is only paying enough attention to absorb the flimsiest cliches of the gun debate.

Finally, it’s conducive, appropriately enough, to political monologue rather than dialogue. As Kimmel’s dismissive comments show, it’s a short step from believing that you don’t need the patronage of the other side to feeling contempt for it. Stephen Colbert isn’t trying to convince anyone; he’s scorning and mocking Trump for the benefit of people who already hate him.

It would have been hard to believe that the old, maligned CNN debate program “Crossfire” would appear in retrospect to represent a golden age of a relative commitment to civil, informed political debate, but here we are.

Johnny Carson once said, “I would love to have taken on Billy Graham. But I’m on TV five nights a week; I have nothing to gain by it and everything to lose.” Stephen Colbert and Jimmy Kimmel, competing for the crown in a much-diminished late-night kingdom, beg to differ, and unfortunately, they’re right.