No matter where you fall on the political spectrum, there is something fascinating about the way certain candidates rise to fame and what keeps them motivated throughout. David Modigliani's documentary "Running with Beto," which premiered Saturday at South by Southwest Film Festival, explores this idea, providing intimate insight into a Texas campaign that drew national attention last year.

The film begins by showing who former El Paso congressman Beto O'Rourke is as a father, a husband and a person, interspersing facts about his political career that are significant to establishing his status an underdog running against Sen. Ted Cruz in the 2018 U.S. Senate race. It's an effective way to open, considering that the film is essentially interested in exploring the human behind the popular politician and why people gravitated toward that persona.

» OUR INTERVIEW WITH THE DIRECTOR: 'Running With Beto' portrays a candidate and a moment

The film documents the entire Senate campaign, from the days when O'Rourke attracted crowds of ten to fifteen people all the way up until his concession speech in front of thousands.

Since O'Rourke's rise in the national conversation and subsequent electoral loss, it is easy to forget that only a little more than a year ago he was far from a household name. One of the more remarkable things about the documentary is that it is able to capture that chronologically instead of just filling in the earlier gaps through recollection. No one knew what O'Rourke's campaign was going to turn into, and not many could have guessed he would become such an influential figure in American politics. But the camera tracks his evolution in a way that also captures a movement currently happening in Texas politics.

While the documentary does often highlight O'Rourke's underdog status and take an admiring view, however, it does not relish in that. The film doesn't portray O'Rourke as a perfect, invincible human being. It takes the time to dive into his more vulnerable moments, whether that's expressing his frustrations to his deputy campaign manager, Cynthia Cano, or his loneliness while away from his family. The toll a Senate race can take on campaign workers, spouses and kids, and what all involved sacrifice in devoting themselves to a campaign, is a narrative often lost in the midst of daily political coverage, especially when a candidate is on the rise. The documentary prominently reflects on that.

This helps paint a fuller picture of O'Rourke's character and his campaign life, which helps to convey the sense that we really are running with Beto, experiencing the real day-to-day stuff, rather than a recap of only big, inspiring moments. What the film does best is show the aftermath of those moments. Two of the most touching scenes in the entire documentary are the long hug O'Rourke and wife Amy share after his debate with Cruz and the solemn moment when the two read the election results in a car.

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In addition to O'Rourke and his family, "Running With Beto" also follows three of his supporters: Amanda Salas, a voter-registration activist and conservative turned Democrat; Shannon Gay, an O'Rourke volunteer from Bulverde; and Marcel McClinton, a shooting survivor and gun-control activist. Each of these individuals share their stories, opening up about their work and the reasons they support O'Rourke. The film follows them from beginning to end, too, which solidifies the emotional weight that the politician's loss carried for his supporters.

Of course, the results of the race are still fresh while you're watching. Yet even with the ending lingering in the back of your mind, it is difficult not to get caught up in the story all over again. The genuine excitement behind the campaign, its team and its supporters is captivating to watch. To its credit, "Running With Beto" speaks to a much larger phenomenon and moment in time.

The film will premiere on HBO this spring. For those who are obsessed with politics and interested in the behind-the-scenes moments of a campaign, or those who are simply fascinated by history in the making or maybe even those who didn't vote for O'Rourke but are intrigued by all the excitement around him, this documentary will satisfy.