Showtime and Bloomberg Politics have combined to attempt a near-real-time dive into the 2016 presidential campaign, “The Circus: Inside the Greatest Political Show on Earth.” But the half-hour that premiered on Jan. 17 looks mostly like a title in search of a series, offering insider access, true, but little that goes beyond the endless election analysis that one can find strewn across cable news, including the program that “Game Change” authors Mark Halperin and John Heilemann host for Bloomberg and MSNBC. So chalk this up as a respectable but ultimately rather tired attempt to lure rubes inside the tent.

Halperin and Heilemann team up with political strategist Mark McKinnon, and they certainly enjoy up-close-and-personal encounters with the candidates, following Ted Cruz and Bernie Sanders as they barnstorm across Iowa in advance of its caucuses. “Evangelicals can smell real evangelicals,” McKinnon muses about Cruz’s ability to peddle himself to that important constituency.

Still, for all the slightly off-guard snippets, “The Circus” — produced close to air, to create a sense of urgency — lacks any real focus. Part of it is a behind-the-scenes look at these reporters on the campaign trail, and there’s certainly a self-aggrandizing aspect to that, with Halperin talking about asking questions that nobody else is, then proceeding to show himself basically content to regurgitate the horserace aspects of the campaign. But then there are extended stretches of, say, Donald Trump delivering a speech at a Florida rally, which one could have easily seen on any of the cable networks.

Perhaps foremost, “The Circus” makes the classic campaign mistake of over-promising — described by Showtime as a “trailblazing real-time political documentary series” — and under-delivering. Because given the saturation coverage of the current election cycle, even a show assembled as close to air as this one risks feeling a trifle stale by the time Sunday night rolls around.

Indeed, if anything “The Circus” represents merely another example of exalting the process of politics — the long bus trips, time spent time away from home and strategizing — without offering much that’s new or compelling in terms of substance. An interview with Sanders, for example, winds up being more about how he competes with Hillary Clinton than where he offers alternatives in terms of policy or core values — hardly a prescription for something that cries out for this sort of premium cable showcase.

Halperin and Heilemann have certainly demonstrated themselves to be both plugged-in reporters and savvy self-promoters, including Bloomberg and MSNBC’s shared carriage of their show “With All Due Respect.” Yet while “The Circus” might be sporadically colorful, at a time when the inside-baseball of politics has become daily grist for the hungry media and its own spectator sport, with all due respect, it’s anything but a game-changer.