Showtime’s weekly half-hour political docuseries The Circus: Inside the Greatest Political Show on Earth returns for its third season tonight. Co-hosts John Heilemann and Mark McKinnon will be joined by new host Alex Wagner, who has replaced Mark Halperin.

The show hit a decidedly uncertain period in October when Halperin exited amid multiple accusations of sexual harassment during his time as political director at ABC News last decade. After deliberating over it, network execs confirmed in early January that Season 3 was a go. In an interview with Deadline, Heilemann addressed the fall limbo, but he and Wagner made the case that Year 2 of Donald Trump has made the show more essential than ever in a crowded political media landscape.

While Heilemann said “there wasn’t that much doubt” about the show continuing, he allowed, “The world is an unpredictable place.” Rather than the hosts, though, he said the concept and approach are the big draw. “Doing this real-time documentary every week and going behind the scenes to try to show people a side of politics they don’t see all the time. The approach, the model for how we cover politics is really the main event.” While chemistry among the co-hosts is also important, Heilemann added, “I think it’s strong enough to survive something happening to any of the co-hosts. If I get hit by a bus tomorrow, I think The Circus would go on. I was hopeful that that would be the case after the events of last October and it turned out that Showtime was down with that.”

Wagner, a former MSNBC anchor who is a contributor to CBS News and The Atlantic, apart from her Circus duties, emphasized the larger mission of the show. “The Circus is must-see television at this point because you need something that distills what just happened in every week that was,” she said. “Because there’s so much going on, you get whiplash following the daily media cycle. Everyone needs something at the end of the week that says, ‘This is what happened, this is what mattered, and here’s how it unfolded.’ The way we get to that is being comprehensive in our coverage and then having an insane, break-neck, late-night editing session at the end of the week.”

Michael Buckner/Deadline

Active production, which is concentrated during the work week and had yet to begin for the season at the time of the interview, will yield a banquet of possible topics for the show to tackle. In its first season, which tracked the 2016 primary season and stretch run of the campaign, the focus was relatively clear, whereas the second season proved as unpredictable as Trump’s Twitter feed. Wagner and Heilemann said they are watching issues like the Mueller investigation, the mid-term elections and immigration, among many others.

“You try to use your judgment about things that might have seemed ephemeral by the time we air. That’s one of the fundamental jobs of journalism,” Heilemann said. “You separate the wheat from an extraordinary amount of chaff. Trump is a non-stop chaff machine.”

Figuring out which developments will resonate days later is the art of the show, he added. “From 30,000 feet, you can point to the big, overarching stories that matter, potentially in the long run for this presidency. … We’re going to be alive to both the big and the small. We’re going to fly at 30,000 feet and also we’ll be down there like a guerilla army crawling on our bellies through the swamp, as the president would like to call it.”