Stephen Colbert honed his now-world-renowned sense of humor as a student at Porter-Gaud.

But Rush Limbaugh was not amused Thursday when CBS announced that Colbert will replace David Letterman as host of "The Late Show" next year. The radio ratings powerhouse told his "dittohead" legions:

"CBS has just declared war on the heartland of America. No longer is comedy going to be a covert assault on traditional American values, conservatives. Now it's just wide out in the open."

As a thrice-divorced admitted prescription-painkiller addict, Limbaugh is an expert on "American values."

However, poking political fun is also an entertaining - and enlightening - American value. And Limbaugh, when not in overwrought indignation mode, provides comic relief of his own on the ominous advance of the Nanny State due to the menace of "low information voters."

As for our hometown boy who's made the big-time, it's true that he has fired nearly all of his ideological shots at conservatives as star of Comedy Central's "The Colbert Report" over the last 8 years.

Then again, what do you expect from a satirist playing a pompous conservative pundit based on Fox News ratings powerhouse Bill O'Reilly?

For instance, on Thursday night's show, Colbert said: "Bill O'Reilly and I have a mutual admiration society. I admire Bill, and so does he."

O'Reilly certainly didn't sound like a Colbert admirer during a Tuesday night lecture against "the grievance industry." On Thursday night, Colbert played a clip from that "O'Reilly Factor" outburst, in which its namesake called him "a deceiver."

From that O'Reilly rant: "Recently Colbert mocked me on the subject of inequality. Only about a million people watch his late-night program at 11:30, but he is the darling of the far-left Internet, which rhapsodizes over him."

Colbert responded: "If I thought for even one second that something I said hurt Papa Bear's feelings, then I, too, am hurt - and to be honest, a little turned on."

Yes, we on the right know O'Reilly's right about the left's counterproductive excesses in the name of "equality."

Yes, in last year's 1st Congressional District special election, Colbert rooted hard for the Democratic nominee.

Hey, she was his sister - Elizabeth Colbert Busch. And her 45 percent share of the vote against Mark Sanford was fairly impressive in our heavily Republican district.

It takes all kinds

So Stephen Colbert, despite growing up on James Island, is a liberal.

So what? So are most (but not all) show-biz sorts. And some of them, including him, are quite funny.

Anyway, Colbert does crack some bipartisan jokes. After showing a clip about a new medication option Thursday night, he said: "It makes sense to treat depression with a horse tranquilizer, because folks, every time I see a horse, I say, 'Why the long face?' "

Sure, that's a stale gag.

But forming a grievance industry against any kind of humor also seems pretty stale.

In Thursday night's opening, Colbert fondly recalled that NBC's "Late Night with David Letterman" began during his first year in college (he started at Hampden-Sydney and later transferred to Northwestern, where he graduated as a theater major in 1986):

"I learned more from watching Dave than I did from going to my classes - especially the ones I did not go to because I had stayed up until 1:30 watching Dave."

Colbert added: "I gotta tell you, I do not envy whoever they try to put in that chair."

And this equal-opportunity laugher's gotta tell you, you should not reflexively resent comic ridicule of the right, left or in-between.

Yet if Colbert really wants to show that his new gig isn't a blatant assault on "American values," he should spread his sarcasm more evenly once he breaks out of his right-wing-blowhard character next year.

After all, lots of us long ago got repeated yuks from the president's preposterous pledges that "if you like your plan, you can keep your plan."

Location, location ...

Another way Colbert can shed O'Reilly's Tuesday night label of him as "one of the biggest mouthpieces for the progressive movement":

The mayors of New York and Los Angeles are urging CBS to put Colbert's version of "The Late Show" in their cities. New York, as the current home of both the Letterman and Colbert programs, looks like the front-runner.

Plus, Friday's Los Angeles Times reported, confirming conservative economic values: "Unlike New York, Los Angeles doesn't have the carrot of a tax credit to dangle to CBS to help persuade it to move 'The Late Show' to the West Coast."

So why not a third way?

Why can't Colbert demand that his new show go not westward but southward?

Why not bring it on home to Charleston, which, after all, is widely hailed as a desirable destination?

OK, so we're not exactly the "heartland of America."

But we should - here and across the land - uphold the "American value" of mocking all sides of the political farce.

Frank Wooten is assistant editor of The Post and Courier. His email is wooten@postandcourier.com.