The original idea was a one-off, or at least that was the intention at the time. Political strategist Mark McKinnon and veteran political scribes John Heilemann and Mark Halperin (top) would shadow the November 2016 U.S. presidential election, peering inside The Greatest Political Show on Earth — a deliberate allusion to Ringling Bros. and Barnum & Bailey’s famous slogan — and revealing the process behind what turned out to be the most unpredictable, divisive and downright crazy political campaign in living memory.

The ending, as it happened, was a new beginning. No one, not even wonks with the street smarts and political savvy of Halperin, Heilemann, and McKinnon (all below) could have foreseen that that man would win the presidency in the end.

This was one story that cried out for a sequel, if for no other reason than those viewers fortunate enough to catch The Circus (Sundays at 8 p.m. ET on Showtime) the first time around were hooked and wanted more. I know I did. 

For The Circus was no lazy, rote reality series masquerading as a serious documentary series. It was a serious documentary series, a genuine piece of cinema that borrowed stylistic elements from The War Room, D.A. Pennebaker and Chris Hegedus’ Oscar-nominated documentary look behind the scenes of the 1992 Bill Clinton campaign, and Michael Ritchie’s 1972 Oscar-winning cinema vérité film The Candidate. That film starred a young Robert Redford as a neophyte candidate for a Senate seat in California reluctantly thrust into the spotlight after his hopeless, longest-of-long-shots campaign against an entrenched incumbent suddenly gains traction, against all odds.

There were no young, starry-eyed neophytes in the real-life campaign for president last November, just a field of older mavericks out to prove a point. Instead of a look at how the sausage is made, The Circus’ story became an exercise in cynicism and dashed expectations, overlaid with a healthy dose of cray-cray as voters voted en masse to repudiate all the old beliefs and prove the experts wrong. 

Boy, were the experts wrong.

And watching Halperin, McKinnon, and Heilemann come to grips with just how wrong they were, in real time, week after crazy week, gave The Circus an edge that separated it from the pack and provided it with some of its most unforgettable moments.

That was then, this is now.

For when The Circus ended, the morning after and facing the mother of all hangovers, it suddenly occurred to them that if ever a documentary series needed a sequel, The Circus was it.

That’s because, even then, on the morning after, it was already evident that the first 100 days with this man in the White House was going to be like none other before it.

And so, now, three weeks into The Circus: Inside the Biggest Story on Earth, is as good a time as any to take stock. For, if anything, the first 100 days — a concept Donald Trump was for before he was against — have proven to be even more cray-cray than anything during the campaign. By now, Halperin, McKinnon, and Heilemann have taken on a dazed and confused look, even as they struggle to prove that, like a broken clock, even experts can be right twice a day and opinion polls are not always utterly, hopelessly wrong.

The Circus is completely absorbing TV, both as a cautionary reality tale and as sheer hellzapoppin’ entertainment. To say it’s unpredictable is like saying Survivor follows a familiar, pat formula. You know there’s going to be a tribal council and group vote at the end of Survivor each week, followed by tears and angry recriminations. The Circus, much like the 100 days it has brought to life, has been, well, real. Not even Dr. Strangelove had a scene where the U.S. president, over a beautiful piece of chocolate cake — the “most beautiful piece of chocolate cake you’ve ever seen” — at his Florida golf resort tells the visiting president of China that, oh, by the way, I’ve just launched a missile strike on Syria.

That’s great material for the late-night TV comedians like John Oliver and Bill Maher, but Oliver and Maher are performing before a friendly audience of like-minded comedy fans. Laugh lines are their stock and trade.

What Halperin, Heilemann, and McKinnon are doing in The Circus is altogether different. They’re shedding light on reality — or trying to, anyway — and the result is a rollercoaster ride of surprises and revelations, some harrowing, some funny, and nearly all of them unlike anything seen or heard before.

At one point during last week’s episode, Heilemann, trying to wrap his mind around a soon-to-happen crisis and how the media might react, said: “Choose your natural disaster metaphor — earthquake, hurricane, tsunami, whatever it is.”

In another moment, Bernie Sanders, walking the hallway behind the stage in an arena where he’s about to hold a rally, tells Halperin that he’s going to step outside for a brief moment of fresh air.

“Fresh air?” Halperin asks quizzically.

“Meet the people, John,” Sanders says back, without missing a beat. “It’s good for you.”

The Circus can also be surprisingly poignant, as when Baltimore Congressman Elijah Cummings (D) told the filmmakers toward the end of last weekend’s episode, “It makes me want to work night and day for the rest of my life to try to make sure we make the best of this situation. This is bigger than Trump. This is about the soul of our democracy.”

The Circus is put together and edited week by week, in real-time, as events happen. That’s one reason why it’s impossible to tell what the upcoming episode is likely to feature.

Yes, the traditional news organizations report each day’s events as they happen — the entire U.S. Senate heading to the White House for a briefing on North Korea, for example, instead of the other way around — but The Circus may well provide an entirely different take on the same event, when this week’s episode airs on Sunday, full of surprise and revelation.

The Circus is absorbing, too, because, despite the political connections of the three wonks at its center, its scope is not limited to Washington, DC, inside the Beltway. The last two weeks’ episodes alone have touched down in Texas, Minnesota, Georgia, California, Virginia, Wisconsin, New York, Pennsylvania, and Kentucky. The Circus visits more towns and cities in 30 minutes than The Amazing Race does in an entire hour.

The Circus will be criticized by some as yet another snide dismissal of the real America by media elites, but that’s not the Circus I see. Halperin, Heilemann, and McKinnon are professionals; they’re bipartisan in their approach, and take the time to tell each side of the story, or at least try, as when Donald Trump, Jr. told Halperin that he believed many of the street protests on the news to be fake, staged by special interest groups with an ax to grind.

There was no doubting the plain-spoken honesty at the end of last week’s episode, though, when hip-hop artist and politically active Run the Jewels frontman Killer Mike told the filmmakers that ordinary, everyday people are more engaged now in politics than ever before, as a result of the past 100 days.

“What the devil has done is force all the saints to sit together and (ask) how do we strategize now for the greater good of us all? Health care, not workfare.”

The Circus is doing its part. This is exhilarating, absorbing filmmaking a shining example of documentary TV at its very best.