If you have any sort of investment in progressive politics or even in the idea of America as a place where anyone can do anything, it will be hard not to start crying at about, oh, a dozen different points in Rachel Lears’ “Knock Down the House.” The documentary, emotional without being overly manipulative, screened at South by Southwest Film Festival in March and hits Netflix on Wednesday.

The documentary follows four U.S. congressional candidates: Alexandria Ocasio-Cortez for New York's 14th Congressional District; Amy Vilela for Nevada's 4th Congressional District; Cori Bush for Missouri's 1st Congressional District; and Paula Jean Swearengin for one of West Virginia's Senate seats. All attempted 2018 Democratic primary challenges (from the left) to male incumbents, and all were endorsed by the Brand New Congress political action committee.

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All four have compelling, hard-scrabble stories. Vilela was spurred to political action after her 22-year-old daughter died of a pulmonary embolism when a hospital turned her away for lack of proof of insurance. Swearengin comes from a long Appalachian line; her town suffered a cancer bloom after years of mining chemicals. Bush was a St. Louis nurse who bore witness to the Ferguson uprising and tried to render aid.

And then there is Ocasio-Cortez, who is easily the most famous face here, what with her jaw-dropping win over former Rep. Joe Crowley (who didn't see Ocasio-Cortez coming and paid the price). AOC, as she is known, is one of the most famous Democrats in the world right now, but her story is no less compelling than those of the other three women, who did not (spoiler warning) unseat their opponents.

All four have similar values: supporting universal, single-payer health care; reclaiming working class votes from the right (in part by being actually working class); not taking PAC money. All four are fantastic to watch, and the movie could have easily run three times as long, following each candidate an equal amount of time.

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But hey, the filmmakers lucked into following Ocasio-Cortez, whose legitimately amazing win was a galvanizing moment for the contemporary left, not to mention the fact that her extraordinary energy pours off the screen. From the first debate where Crowley sent a proxy (jeez, that poor woman) to Ocasio-Cortez and her boyfriend at home in their tiny apartment to the debates Crowley actually showed up for, Lears got the sort of emotionally intimate access of which filmmakers dream.

So when the big days come — Lears picked candidates such that their primaries would not be on the same day, which would have been impossible to film — you are right there with each of the hopefuls, through three tough losses and a win so surprising (even when you know it is going to happen) that the joy therein is completely tangible.