President Trump’s itchy trigger finger has many Americans worried. But for a group of staffers clustered in a narrow office building attached to the Ed Sullivan Theater in New York, the fear is his antics may trigger another type of fallout: a “live show situation.”

No matter how much work goes into the jokes crafted for the monologue and other comedy bits for CBS’ “Late Show With Stephen Colbert,” the staff knows much of it could be scrapped just before its host tapes the program before the audience. “Many’s the night when we have to throw the whole thing out after rehearsal,” explains Colbert. “There’s never a point when the show is so locked that we won’t change it — literally minutes before I go onstage.” In May, when FBI director James Comey was fired, for example, Colbert had already delivered his monologue, only to be told of the breaking news after he was done, recalls Chris Licht, the late-night show’s executive producer. Colbert immediately taped a new version. “My heart is thumping. My pulse is racing,” Colbert told the crowd. “We’ll have more on this tomorrow, when they scramble to cover the whole thing up.”

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That instant response to headlines has helped the host skyrocket to the top of the late night ratings charts, but on a recent visit to his office, he admits it’s also left him feeling “hung over from the news.” Just the day before, he and his staff had to whip up an entirely new opening after President Trump let loose during a press conference, saying both sides were to blame for the August clash between white supremacists and protesters in Charlottesville, Va. “Last night was probably the fastest we wrote a monologue ever,” Colbert says. “We didn’t even get to see the thing we were writing about.” He can’t resist throwing in a punch line: “I almost pulled a hamstring last night because we went from zero to sixty so fast.”

Staying right on the latest headlines in a nation addicted to them has lent Colbert and his “Late Show” new momentum, and the host says delivering jokes related to whatever the nation is talking about has become his modus operandi. After a rockier-than-expected start on CBS upon taking over the show from David Letterman, Colbert has seen his viewership surge. NBC’s “Tonight Show Starring Jimmy Fallon” continues to win the most viewers in the demographic advertisers covet, people between 18 and 49, but Colbert now has the biggest total audience — putting CBS in a position in late night it has not enjoyed in decades. “I think in the long run, Jimmy Fallon is going to do just fine,” says Rick Ludwin, the executive who for years supervised NBC’s late-night programs and their hosts, including Johnny Carson, Letterman and Conan O’Brien. “But there’s no question that Colbert has found his voice.”

Now the host is about to take that power out for a high-profile spin.

Though he made an appearance at the Grammys, hosted the Kennedy Center Honors and made a notable breakthrough telling jokes at the 2006 White House Correspondents’ Dinner, Colbert has never hosted one of the major annual awards telecasts. On Sept. 17, he will take a crack at the Emmys. He’s had a pile of jokes at the ready since late August.

He’s well aware, though, that he’s walking a tightrope. The people who tune in to “Late Show” want to hear his take on the headlines, and they know he will rail incessantly at President Trump. But the people who watch the Emmy Awards come from a larger cross-section of the country. They want to laugh, sure, but they may not want the politics.

Colbert thinks he can maintain his balance. “We are storytellers: The story we are telling is what happened on television this year,” he says. “It’s not a political monologue, but you can’t keep politics out of it, because politics was the biggest TV story this year.” He adds: “The biggest story of the year is not ‘Westworld.’ It’s not ‘The Handmaid’s Tale.’ It’s not Milo Ventimiglia’s luscious abs. That’s not what we cared about,” he says. “The biggest TV star of the year is Donald Trump.”

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No late-night host on broadcast has launched as sustained a campaign against a sitting U.S. president as Colbert. Yes, Seth Meyers, Samantha Bee and Trevor Noah have all made plain they cast a wary eye on the current White House, but Colbert’s daily 11:35 p.m. roost is part of the genre’s first, most potent wave. He comes on after the late local news, the hour most likely to catch the greatest attention.

Even though Carson hosted Ronald Reagan’s 1981 inauguration, viewers never knew where he stood on the issues of the day. Colbert has made his feelings about the president abundantly clear. Fallon has added some politics to his monologue, including a heartfelt callout against the recent Charlottesville fracas, and Jimmy Kimmel has challenged Trump voters in no uncertain terms. Colbert, however, does it night after night. After night.

“I feel like I went on a bender last night,” Colbert says. “But all I did was watch the President of the United States and then watch CNN to see who would burst into tears first, Van Jones or David Gergen. It turned out to be Van Jones, but if David Gergen were capable of expressing human emotion, I think he’d be clawing his own eyes out.”

Colbert rose to renown playing a bombastic, loudmouthed caricature of a TV host on Comedy Central’s “Colbert Report,” winning a bucketful of Emmys, but when he talks about Trump, he says he’s speaking from the heart. “We have a team of writers, but I would not tell a joke the intent of which I do not share,” he says, confessing that the news often makes him so upset he wishes he had a show like his that he could watch at the end of the day.

“The story we are telling is what happened on television this year. It’s not a political monologue, but you can’t keep politics out of it, because politics was the biggest TV story this year.” Stephen Colbert

But he says it will take more than late-night mockery to truly effect any kind of change in Washington. “Comedy will not stop him,” he says, referring to Trump. “The democratic process — that’s it,” he adds. “The democratic process will stop this guy. It’s the only way. That’s it.” And, he adds, “for the Republican Party to grow a pair. Just drop a ’nad, and do what you know is right. And that won’t happen until they lose the House or the Senate. And then, ‘Katie bar the door.’”

Colbert says his political views were formed in the heat of the Nixon presidency. As an elementary schooler, he would come home only to find that instead of being able to watch “The Munsters” or “The Three Stooges” on TV, all he had to entertain him was the Watergate hearings. “It was on all the channels. I was pissed off, because I didn’t want to watch that and there were no DVRs at the time — until my sister Margo sat me down and explained why it was important,” he says. “She explained to me who Sam Ervin was and what was going on with John Dean.”

Then he was hooked. “I have been a news junkie for a long time, but certainly, a mistrust of power and authority, the ur-distrust, comes from Nixon,” he says.

His newfound success has lent him confidence to mull recalibrating parts of his show. Early in his CBS tenure, “Late Show” featured guests like Apple CEO Tim Cook and former Vice President Joe Biden. Colbert is eager to spark more thoughtful discussions on his stage, perhaps in the back half of the program — after he has led with a better-known celebrity.

He rattles off a list of guests he’d like to have on: Neil deGrasse Tyson, Brian Greene, George Saunders, Jake Tapper, John Dickerson, Al Franken. The segments, he says, could “expand the palette of what is acceptable in late night.” He’s hopeful that his viewers will embrace discussions with people who energize him personally.

He’s also gearing up for an animated series on Showtime that will feature the cartoon version of President Trump that has appeared on “Late Show,” along with counterparts of Trump family members. Colbert says the 10-episode series, which might debut before the end of the year, will shed light on what happens in the White House when the public isn’t watching. “It’s what you don’t see on camera,” he says, reluctant to give too much away. “It’s about current events, but it’s about the lives of the people who work there.”

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HBO’s recent decision to scrap a proposed animated series from Jon Stewart that would have tackled current events and the news business presents “an opportunity,” says Showtime CEO David Nevins. Thanks to digital technology, staffers will be able to weave in a few minutes of topical humor each episode, he says. “These characters live in a computerized environment, so you can add material at the last second for a certain number of minutes per episode,” he explains. “If we were working on the series this week, we could talk about the hurricanes. We could talk about DACA. We could talk about North Korea.” He suggests the program might have elements of “The Simpsons” and “The Office,” with Trump “somewhere between Michael Scott and Homer.”

It’s hard to separate Colbert’s ascendancy from the man now living at 1600 Pennsylvania Ave. So what happens if Trump leaves office? Will “Late Show” lose its edge among the broader audience that has tuned in? Will a competing show less focused on the headlines instead seize the moment?

Leslie Moonves, the CEO of CBS Corp., suggests it’s less that the show is a beneficiary of Trump than the fact that Colbert and Licht had found a center by the time voters went to the polls. “The show had reached a very solid position before the election, and they were ready to take off when the Trump stuff happened,” says Moonves. Even so, he notes, the viewer surge is remarkable. “You don’t see that in late night,” he says. “It’s like trying to turn around a boat.”

Licht, who has had a hand in launching both “Morning Joe” and the current incarnation of “CBS This Morning,” believes the audience is tuning in for Colbert, not for Trump. “We aren’t built to be a Trump show. We are not built to be a political show,” he says. “They are coming to hear what [Colbert] has to say about what’s happening in the world, period.”

Should the Trump era come to an end, Colbert is satisfied that he and the show have hit their stride. “The national conversation has been swallowed by him and he’s in front of the lens all the time. He doesn’t want it to end, and in some ways, we serve the news cycle, we serve the conversation, and whenever that changes we will talk about something else,” he says. “Maybe no one will care about anything else as much as they care about him – on either side – and so that could temper the intense interest in what any of us in late night are doing, because it’s been, you know, I hesitate to use the word ‘good,’ but it has been strong notice across all of the late-night shows,” Colbert says. “If it’s not him, it may temper interest in late night, but I don’t see it ending. But what I know is that no matter what, we will never stop keeping the doors of the show open until the last minute, because now we know what the show is about.”

Andrew Hetherington for Variety

That lesson was served up to him under extraordinary circumstances. On election night last year, Colbert hosted a live special on Showtime that, as originally envisioned, was going to have him roll out funny bits and speak to opinionated guests as the tally for the presidency came in. But those plans had to be abandoned. The audience in the Ed Sullivan Theater was not happy with the unfolding news, and the crowd’s fear and surprise colored the evening, turning what should have been an upbeat night into the equivalent of a televised wake. “It feels like an asteroid has smacked into our democracy,” said comedian Jena Friedman, one of the show’s guests. “Get your abortions now.” The audience gasped as Colbert delivered news about voting results from various states. Within 40 minutes, he says, he began drinking bourbon onstage.

Nevins came out from the control room to speak with Colbert while Elle King belted out a song. He says he advised the host to “throw out the script and just emote with the audience. That made him seem very human.” Colbert and Licht say the team agreed to cut the sketches — no one was laughing — and wing it. There were no more bits to rely upon, just guests, their horrified reactions and Colbert’s real-time responses. He didn’t want to end the show until the results of the election were close to being known, and when he did decide to wrap, he delivered an unrehearsed monologue, asking, “How did our politics get so poisonous?”

By the end, he says, he realized he had hit on a new “Late Show” foundation. “The last 10 minutes of that election show were honest. They were honest, and that was a turning point for us,” he says. “After that, we knew I could never do this show without at least attempting to keep my emotional skegs in the water.” Each monologue, he adds, represents “an attempt to be honest with the audience so we can have an intimate relationship.”

Small wonder that Colbert, who for years had to portray that fictional character on Comedy Central, has begun to feel comfortable onstage in his own skin. He has gladly donned the guise of his old friend on occasion for “Late Show” bits, but says he’s ready to just be himself from now on. “I think I have an intimate enough relationship with the audience that they don’t want him between us, do you know what I mean?” he asks. “The last time I did it, they enjoyed it, but I think they enjoy me being me too — and so do I. That’s why I took this gig.”

Go behind the scenes of Colbert’s cover shoot below.