A foe of population growth, Lee had apparently decided that shows like “Kate Plus Eight” and “19 Kids and Counting” were pushing the planet toward destruction. “All programs on Discovery Health-TLC must stop encouraging the birth of any more parasitic human infants,” he decreed, before moving on to demand solutions for “global warming, automotive pollution, international trade ... and the whole blasted human economy.”

By the end of the day, the hostages were safe, Lee had been killed by police, and TLC's fall lineup was preserved. But the debate about the hostage-taker's politics was just beginning.

Conservatives and libertarians dubbed Lee a “liberal eco-terrorist” inspired by a “green climate of hate.” They pointed out that he traced his political “awakening” to Al Gore's apocalyptic rhetoric. They cited an F.B.I. statement calling eco-vigilantes America's “No. 1 domestic terrorism threat.”

This was all a little ridiculous. But of course it was really an attempt to turn the tables on liberals, who have spent the last two years linking conservative rhetoric to hate crimes and antigovernment maniacs. (It's a hard habit to break: the liberal site ThinkProgress.org quickly suggested that James Lee was actually a right-wing extremist, because his hostility to “parasitic human infants” extended to the children of illegal immigrants.)

To some extent, partisans persist in these arguments — “your side encourages extremists!”; “no, your side encourages extremists!” — because America really is rife with wild and crazy sentiments. The belief that Barack Obama is secretly a Muslim (apparently held by nearly 20 percent of the country) gets the headlines. But as the George Mason law professor Ilya Somin has noted, national opinion polls reveal support for numerous far-out or noxious-seeming notions.

There's the 32 percent of Democrats who blame “the Jews” for the financial crisis. There's the 25 percent of African-Americans who believe the AIDS virus was created in a government lab. There's support for state secession, which may have been higher among liberals in the Bush era than among Republicans in the age of Obama. And there's the theory that the Bush White House knew about 9/11 in advance, which a third of Democrats endorsed as recently as 2007.

So are we a nation of potential James Lees, teetering on the brink of paranoid violence? Not necessarily. As the libertarian writer Julian Sanchez has pointed out, it's worth taking all these polling responses with a substantial grain of salt. For all but the hardest-core conspiracy theorizers, they may express what Sanchez calls “symbolic beliefs.” These are “propositions you profess publicly” but would never follow through on, because they're adopted as a kind of political and cultural statement rather than out of deep conviction.

Consider the apparently widespread notion that George W. Bush knew about 9/11 in advance. If true, it would suggest that Bush was not merely a bad man or a bad president, but an evil genius on a shocking scale. But as Sanchez notes, “you did not really see a lot of behavior consistent with millions upon millions of people being seriously convinced that their president was a treasonous mass murderer.” Nobody planned an insurrection; few people fled to Canada. Instead, liberals organized for Democratic candidates, as though Bush were an ordinary opponent rather than a stone-cold killer.

The same is true of conservative conspiracy theorists today. Tuning in to Glenn Beck or joining your local Tea Party seems like a woefully insufficient response to the possibility that Barack Obama is a Manchurian candidate groomed from birth to undermine democracy and impose Shariah law. But if we understand those paranoias to be symbolic beliefs, rather than real convictions — an attention-grabbing way of saying, “I consider Obama phony, dishonest and un-American” — then conservative behavior makes a lot more sense.

Such beliefs can still be dangerous. The line between what's symbolic and what's real isn't always clear, and a determined demagogue can exploit symbolic beliefs as well as real ones.

But obsessing about the paranoia of the masses is often a way for American elites to gloss over their own, entirely nonsymbolic failures. In the Bush era attacking the conspiracy theories of the “angry left” made it easier for conservatives to avert their eyes from the disaster the Iraq war had become. Today, establishment liberals would much rather fret about the insanity of the Republican base than reckon with the unpopularity of Barack Obama's domestic program.

Some fretting is justified. (Just ask the Discovery Channel.) But over all, Americans still have more to fear from the folly of establishments than from the paranoia such follies summon up.