Stephen Colbert is host of the 'The Late Show' on CBS. (Invision/AP)

The expectation was laid out, plain as can be, in the first reports of Stephen Colbert’s hiring by CBS to succeed David Letterman as host of “The Late Show.”

From the New York Times on April 11, 2014:

The news of Mr. Colbert’s appointment inflamed conservative commentators like Rush Limbaugh, who said CBS had “declared war on the heartland of America.” But CBS executives made it clear that they expected Mr. Colbert to broaden his appeal when he moved to the medium of late night on a network.

Broader appeal. That’s what Colbert — famous for his satirical portrayal of a conservative commentator on Comedy Central’s “Colbert Report” — is supposed to be going for in his new job. It’s important because, even on an average night on CBS, Colbert is playing to a bigger audience (more than 3 million viewers) than he did on his best night on cable (2.5 million for his curtain call last December).

Back when he was hired, there was a good deal of chatter about just how liberal Colbert actually was. He admitted during his time at the "Daily Show" that he had discovered his liberal politics there, but even some conservatives seemed to respect his brand of comedy, and there was actually relatively little backlash against a guy whose faux conservative alter ego was hardly flattering for the right side of the political spectrum.

And yet, two months into the gig, the 51-year-old funnyman could be alienating real-life conservatives with his persistent brand of lefty wisecracks. And that could be a problem for CBS, which, like all of the major networks, will want to attract Democratic and Republican viewers throughout the next year of presidential electioneering.

In the opening week of November, for the first time since his Sept. 8 debut, Colbert fell to third place in the critical 18-to-49-year-old ratings demographic. Jimmy Fallon, host of NBC’s “Tonight Show,” has been the runaway leader for most of the fall season, but this was the first time Colbert trailed ABC’s "Jimmy Kimmel Live." Last week, it happened again.

A survey of late-night comedy viewers, conducted Nov. 6-10 and published Friday by the Hollywood Reporter, offered insight into what might be going on. Colbert’s CBS audience is 47 percent Democrat and just 17 percent Republican, according to the findings of D.C.-based polling firm Penn Schoen Berland.

Compare Colbert’s partisan breakdown with the nearly even splits of Fallon (36 percent Democrat/31 percent Republican) and Kimmel (34/33), and it’s apparent that Colbert’s competitors do the whole broad-appeal thing better than he does. For now, at least.

CBS did not respond to an inquiry about Colbert’s ability to attract a wide audience during the campaign. But the current dramatic skew could have something to do with stuff like this:

Remember, as we’ve already told you, opposition to the resettlement of Syrian refugees is hardly a fringe position.

There’s also stuff like this:

Support for same-sex marriage has risen dramatically in recent years, but more than a third of the country still opposes it. Again, this isn't a fringe population.

Colbert knows how to bring down the house by painting conservatives as a bunch of backward xenophobes. He’s one of the best at it. But huge chunks of the electorate probably won’t be laughing along — or, worse, even tuning in. Not unless he balances things out.

Late-night comedians Jimmy Fallon, Conan O'Brien, Seth Meyers and others poked fun at Democratic presidential candidate Bernie Sanders this week. From his performance in the latest debate to joining Snapchat, the hosts weren't short on material. (The Washington Post)