Three names who changed the channel on late-night TV: Stewart, Colbert and Trump

The radical reinvention of late-night television recently hit new ratings heights, with a moment that cemented the forceful blend of partisan politics and sharp-edged comedy as the new recipe for success.

And it was the culmination of a revolution in viewer expectations that began with the audience for one man and one show a long time ago.

First, the moment: Final Nielsen ratings for the 2018-19 season came out last week, and the intensely political “Late Show with Stephen Colbert” won the crown for overall audience by an unusually wide margin — 3.8 million viewers, to 2.4 million for “The Tonight Show” and 2 million for “Jimmy Kimmel Live.” More importantly, Colbert was first in advertisers’ favorite demographic, viewers in the 18-49 age group. That hadn’t happened in more than two decades, since the 1994-95 “Late Show” season hosted by David Letterman.

Colbert’s achievement marks a sweeping shift away from a template set by “Tonight Show” host Johnny Carson in 1962 and carried on by successor Jay Leno and his competitors: Late-night was a place for light laughs and easy banter; political jokes were mild and bipartisan. The idea, as Leno noted earlier this year, was to give viewers a comfortable, familiar escape from the troubles of their long day.

Leno was reliably bipartisan in his approach; magazines even wrote articles trying to guess where he stood politically. When I worked at NBC, I talked to Leno the day the Monica Lewinsky scandal broke. He was overjoyed by the news — not out of any hostility toward President Bill Clinton but because he knew sex scandals were comedic gold. He was grateful for the gift.

The tone is so different today that Leno felt the need to call for a return to “civility” in late night. That loss of comedic boundaries was clearly super-charged by Donald Trump’s campaign and presidency, but credit (or blame, depending on your Nielsen numbers) also goes to a generation of viewers who transformed what was expected of late-night. They made Jon Stewart a star.

In 1999, the little-known Stewart was hired by Comedy Central, a little-known cable channel, to take over a little-known half-hour comedy called “The Daily Show.” The program back then mostly skewered TV news conventions, but Stewart moved into edgy political satire during the George W. Bush years. It worked. Ratings tripled between 1999 and 2008.

More significantly, younger portions of Stewart’s audience actually saw him as a major news source. “The Daily Show” delivered headlines with an iconoclastic and irreverent political point of view which felt more “true” to those viewers than a traditional newscast.

Twenty years later, that once-young audience is in its 40s and early 50s — the typical demographic sweet-spot for broadcast networks. When Stewart left “The Daily Show” in August 2015, those viewers began looking for a new place to call their late-night home.

Luckily for them, Stephen Colbert, former “Daily Show” cast member and host of his own political satire program, debuted on “The Late Show” a month later. But he wasn’t the Colbert they knew. Trying anxiously to follow the Carson/Leno formula, the comedian largely avoided politics on his CBS show — and the audience largely avoided him.

But then the 2016 campaign kicked into high gear. Colbert got a new team behind-the-scenes and encouragement from top brass to try the cable template he developed with Stewart on mainstream broadcast television.

It was a nerve-wracking gamble. In the old playbook, Colbert’s numbers should have plunged, with audiences deserting him in droves for the sunnier Jimmy Fallon, who famously mussed up candidate Trump’s hair in a light-hearted “Tonight Show” moment right out of the Carson/Leno blueprint.

The opposite happened. A generation of viewers raised on “The Daily Show” and its spin-offs rushed toward their version of comfortable, familiar late-night: a program that wrapped up the day’s political news in a package of pointed satire. Fallon, meanwhile, was slammed for his gentle approach to Trump — and 50 years of TV programming custom went out the window.

Many Hollywood executives, reluctant to discard decades of established media dogma, suspect viewer exhaustion with rough-and-tumble political humor is right around the corner. But they’ve been saying that for a while, and the trend shows no signs of abating. Today’s viewers want the kind of TV they grew up on, not their parents’ late-night. Judging by the latest numbers, the sharp mix of politics and comedy may simply be — like so much else churning through Washington these days — the new normal.