In his second night as host of The Colbert Report, Oct. 18, 2005, Stephen Colbert made a joke that wasn't really a joke. Over the course of the show's run, he promised, viewers would be treated to installments in "a 435-part series" called Better Know a District.

He didn't make it to 435, but he almost broke triple digits. During its just-under-a-decade on the air, the show visited a full 94 Congressional districts in the U.S. (and one in the U.K., because it's a comedy show, after all), and that's not counting the districts he revisited. He explored major industries, minor policy issues and daily life all over the country, which, viewers were gently reminded, is huge.

No national news program in history has devoted that much time to systematically covering individual members of Congress—why would you? It's boring unless there's a scandal, right? With one of his first initiatives, Colbert proved, as he so often would, that conventional wisdom about what interests Americans was wrong.

Colbert is ending his half-hour late-night comedy news show The Colbert Report, one of the strangest and most wonderful television series ever to exist, to take a job with CBS as the host of the Late Show when David Letterman retires.

It's a signal honor, one that comedians spend their entire lives dreaming about, and yet if you've loved the Colbert Report, the move might also seem like a step down.

Letterman is widely beloved, even despite a fairly sleazy intraoffice sex scandal in 2009. He's funny, he's canny, he's political when he feels like it. But the great success of The Colbert Report is not merely that its heart is in the right place but that its head is right there with it. The Stupid Human Tricks on Comedy Central between 11:30 and midnight are performed almost entirely by our elected officials, with the occasional exceptionally dumb civilian, and Colbert's triumph isn't that we laugh at them; it's that we care enough to laugh at them.

Colbert made the case that the grind of local politics and legislative minutiae was not only interesting, but also vital and, best of all, funny.

The apogee of the show's wonkery probably came in 2011, when Colbert formed a super PAC to illustrate exactly how terribly overreaching the legislation enabling super PACs was. Everywhere else, the subject was mind-numbing; Colbert made it urgent and real.

Like most top-tier comedians, Colbert's success is preceded by a long career in which he did almost nothing but comedy in one form or another, often invisibly. After graduating Northwestern (which has a great interview with him here) in 1986, he toured extensively with Second City, at first as an understudy for Steve Carrell, with whom he later had the recurring Daily Show segment Even Stevphen.

Colbert worked on several TV shows, notably SNL, Comedy Central's short-lived Exit 57, and even a few offbeat segments for Good Morning America (yes, it's shocking to see him so young, but some of that is the lack of hair gel). In fact, he preceded Jon Stewart at The Daily Show—Colbert started in the show's second season under Craig Kilborn, working in a format that doesn't look too different from Colbert's taped segments from last year or last week: veterans' affairs, local political scandals, unfairness and absurdity—these were a few of his favorite things, and remained so through the end of the Report.

And perhaps it was because he had developed such a credible impression of a Beltway journalist that the White House Correspondents' Association decided to invite him to entertain at the group's annual dinner in 2006, where he did maybe the single ballsiest thing a comedian has ever had the opportunity to do: tell a sitting president, through the thinnest possible veil of irony, exactly what he thought of him. Then he let fly at everyone else in the audience.

Colbert, even with a shtick that owes a lot to the bloviating of pundits on talk radio and Fox News, particularly Bill O'Reilly, never spent as much time as Stewart on media criticism. At the White House Correspondent's Association dinner, he made it clear that it wasn't fear or a lack of interest that kept him from addressing the news media directly—it was contempt.

"Over the last five years you people were so good, over tax cuts, WMD intelligence, the effect of global warming," he told the stone-faced reporters. "We Americans didn't want to know, and you had the courtesy not to try to find out. Those were good times, as far as we knew."

For the most part, Colbert's act rarely seems contentious or cruel; his consistent good humor is probably a lot of what helped land him at CBS, a network now more or less unique in its devotion to broad appeal. But the South Carolina native still has a red-state liberal's anger at the cynical pandering of O'Reilly, Sean Hannity and Greg Gutfeld—Colbert was calling O'Reilly "a fucking egomaniac" on his show as recently as October (see above).

O'Reilly and Stewart have something of a cordial détente after all these years; Colbert's appearance on The O'Reilly Factor might be the most uncomfortable seven minutes ever televised, and watching the footage again, it looks a lot like Colbert knew it would be when he took the interview offer.

Colbert might very well take that same spirit of anarchy and the fanatical commitment to satire that has marked even the gentler parts of his show to CBS. It's hard to imagine his succeeding on such a large scale, but then, Colbert's entire career has been tilting at windmills and, to everyone's surprise, knocking them down.

It's also possible that he'll mellow. For his own sake, that would probably be a good thing. Fearlessness is hard work, and the list of comedians who lived to a ripe old age and stayed fierce is not long (in fact it's mostly just George Carlin).

Colbert's a whiz with advertisers—one of his funniest segments is a vaguely dystopian performance of the Wheat Thins brand memo, which Wheat Thins loved—though it's unlikely a political comedian enjoys that part of the job. He could indulge his nerdier streak, too—he interviewed Smaug, the dragon from The Hobbit, last week, and his Star Wars geekery is unparalleled. That kind of thing is fun, and it's always going to require less work and get more attention than the thankless public service stuff he's done out of what looks suspiciously like a sense of duty.

So which will it be? Political, counterculture performance art in one of the most popular venues on television, or a kinder, gentler truthiness?

Time will tell, obviously, but Colbert is taking his entire writing staff to the new show, and most likely he and they will give us a third thing. Hopefully it will be as educational, and as judicious with his surprisingly deep reservoir of anger, as Colbert's work has been so far.