The most fascinating thing about Josh Kriegman and Elyse Steinberg’s political documentary Weiner (B-) is that it exists at all. It’s not the filmmakers’ fault that their subject, New York Representative Anthony Weiner who resigned in the disgrace of a sexting scandal and embarked on an unsuccessful bid for redemption in the 2013 NYC mayoral race, proves to be so stupefyingly unsentimental. The whole story is about a man being unable to shake off a self-fulfilling narrative and the inability in the 24-7 internet news cycle to change the subject. The sunny first act presents a not completely absurd premise with spouse and supportive strategist Huma Abedin at the helm of giving her humiliated husband a second chance. Calls to donors go well, and it appears they’re turning a corner. But as soon as the words “Carlos Danger” and the real-life partner in cyber-hijinx Sydney Leathers come into the picture, it’s a battle to the bottom of the political barrel. An epic skirmish with a heckler and even a crying baby in the election booth are mounting symbols of the mayhem. The film isn’t funny or poignant enough to really stand on its own or convey any universal truths. Like its main character, it stumbles around a good bit. Huma and the political handlers all look like they were taken for a ride. The film certainly doesn’t separate the twin legacies of the man as lawmaker and lothario. It’s instructional, perhaps, about how not to live your life or to run a campaign. If the genre is cautionary tale, it gets high marks.