It’s probably a sign that the Democratic Party’s presidential field is too large that Beto O’Rourke’s flagging campaign is hoping that a documentary that features him calling himself “a giant a**hole” in front of his staff will provide a boost in the polls. Some people saw the film in March when it premiered at the SXSW conference, but it will get a much wider audience beginning Tuesday night when it airs on HBO. They’ll be treated to several examples of O’Rourke using casual profanity, and not always in a self-deprecating manner. [cut] So, with little to lose and not much...