It happens after every shocking act of violence against a public official. Or just a bitterly disputed election. Americans are told we must tone down our rhetoric. It’s too wild, too provocative, and just plain dangerous.

This has been going on at least since the presidential election of 1800, which would have made the last one, in 2008, look like a model of civility. Politicians still fought duels in that supposedly golden age of civility. The country lost the greatest secretary of the treasury it ever had that way.

In a contemporary tribute to civility, Keith Olbermann is leaving his news show on MSNBC, which will come as a surprise to those who never noticed he was there. For nobody pretends MSNBC is the most watched network in the country. But he was a fixture there. A big fish in a little pond. Or rather muddy puddle.

Mr. Olbermann has been forgotten with lightning speed. Indeed, he was scarcely noticed when he was on the air – except when he and Ann Coulter got into another catfight. Which was frequent but not very entertaining. Just a lot of mutual screeching. Lots of political commentary is like that these days.

Now if only somebody would find nice, quiet office jobs for Glenn Beck and Bill O'Reilly, who tend to rant and rave, or at least smirk, from the other, rightward side of the political spectrum. It’d be nice if the rise of civility were a bipartisan phenomenon.

Despite their striking differences when it comes to the flashiest, most superficial of subjects, mainly politics but occasionally the larger culture, the Olbermanns, Becks and O'Reillys share a common, deadly-dull quality: a closed mind.

It’s as if, in a world of ideas, they’d chosen only one kind to forever hone – noisily, reflexively, endlessly. But at least they remain consistent: Whether liberal or conservative, they stay kneejerk liberals or kneejerk conservatives.

These polemicists of the air may generate a powerful current in American public opinion, but it’s a closed circuit, lighting only one ever-sizzling bulb. Any light they shed is so confined it seldom extends beyond their own devoted fans.

This is the fate of all ideologues; they have no more contact with reality than the chained prisoners of Plato’s cave, forever entranced with shadows, their vision distorted by their fixed positions.

But the analogy is scarcely fair – to Plato’s figures – for the kneejerks of today’s commentariat are scarcely prisoners; they have forged their own chains. Willfully.

In the end, these televised showmen fail the test that ought to be applied to every commentator on the passing events of passing days: Do they raise the standard of public discourse? Do they break through the bounds of conventional political commentary to rise above the battle below? Do they aspire to the level of a Burke or Tocqueville or the authors of the Federalist Papers? Or do they just mouth off?

Those founding fathers, lest we forget, were just writing for the newspapers of their time, yet they refused to pander to the lowest common denominators of public opinion. Their commentary on the ephemeral issues of their time would long outlast many of the issues themselves. We still read Madison and Hamilton today. Or at least the more discerning of us do.

Instead of pandering to public opinion, those gentlemen sought to raise its level to their own. Yes, they set a high standard for inky wretches to aspire to, but a commentator shouldn’t settle for anything lower, not if he wants to retain the respect of his audience – and his own.

Yet this much can be said for Olbermann, O'Reilly, Limbaugh and plentiful company: They do not represent their ideas, however limited, to be anything but opinion. They do not pretend to be objective. In that way, they’re shining examples of fair merchandising. Unlike, say, today’s New York Times, where the most effective editorial opinion may be found in the news columns. Or the “news” reports on NPR, where an honest commentator may be found entirely too honest and so have to go. (See the case of Juan Williams.)

At least the Keith Olbermanns and Bill O'Reillys are not in any way on the public dole, unlike the smoothies at NPR. Whatever criticism they merit, which is a lot, they’re not doing their show on your tax dollar.

© 2010 TRIBUNE MEDIA SERVICES, INC.