What do Michael Moore’s obscene-grannies ad, that creepy Obama-kiddie-body-snatchers song, and Joss Whedon’s Romney-zombie-apocalypse rant have in common? Each represents an appeal to the Democrats’ fundamental constituency: the Dumb Vote. Or, as I call them, Jon Stewart’s audience.

It is always surprising to me how highly regarded Mr. Stewart is among a certain segment of high-affect/low-information voters. Unlike his colleague Stephen Colbert, who is a gifted satirist, Mr. Stewart is a one-trick snark artist whose shtick is fundamentally cowardly. He sometimes wants to play rough with the more serious crowd, as in his famous denunciation of Crossfire, but when he is seriously challenged on anything of substance, he retreats into his aw-shucks-I’m-just-a-comedian cave.

A disturbingly large number of people get a great deal of their news and views from Mr. Stewart’s show and similar outlets, and they operate politically along the same model as the show, which is to say they substitute banalities for analysis and posturing for thinking. Understanding, for example, the real substantive differences between Mitt Romney and Barack Obama on taxes takes a good deal of work. Because the Dumb Vote is not willing or able to do the work, things unfold like this: Barack Obama complains that Mitt Romney plans to give “tax cuts to millionaires and billionaires and corporations,” Jon Stewart turns that into something in the approximate form of a joke, and the Dumb Vote har-hars about it, nodding its collective head at its own pseudo-insight. If you happen to complicate that view with an incongruous fact — for example, that Barack Obama proposes to reduce corporate tax rates — then the discussion just moves on to another joke: binders full of women, Mormon polygamy, whatever.

It is only in that kind of emotionally based, information-free environment that something like Mr. Moore’s vulgarity can thrive. I would not say that it’s likely to change minds, because minds are not what is at work here. Think about the rhetorical structure of Mr. Moore’s ad and its strategy. The point of the ad is to argue that Republicans are engaged in “voter suppression” because in some states they have insisted on such straightforward integrity measures as asking for a legitimate photo identification card for voters, or purging felons and other ineligible voters from the electoral lists. Mr. Moore, being a crafty rhetorician, never presents an argument that these measures are unwarranted or unfair; he simply assumes the sale, knowing that the not-very-bright among us will be giggling at the prospect of old ladies using foul language, and therefore unable to think critically about the implicit argument of the advertisement — because they are, simply put, not smart enough to giggle and think at the same time.

Mr. Whedon’s version of this is more tasteful (it would be hard not to be) and slightly more of the moment, with its ironic endorsement of the ever-popular zombie apocalypse. But take a listen to the issues that Mr. Whedon is worried about: “overpopulation,” “ungoverned corporate privilege,” and his belief that Mitt Romney’s vision is an America in which we “stop pretending we care about each other.”