In this bit from the October 28 edition of HBO's Real Time with Bill Maher Maher takes issue with false equivalency, aka both-siderism, as in "Both sides do it." A lot of the time they do, but not to the same degree. Warning to those with sensitive ears: This is Bill Maher on cable.
Maher is a bit incorrect in his characterization of Politifact's ratings. Politifact doesn't evaluate everything a candidate says, only those substantive assertions of fact that sound questionable. So it isn't true that if P percent of a given candidates' statements examined by Politifact are rated false, that means the candidate is lying P percent of the time.
In addition, Maher mistakenly says that the percentages he quotes are for statements rated at least somewhat false. In fact, the numbers in question represent the fraction of statements rated "Mostly False," "False," and "Pants On Fire." They don't included the categories "Half True" and "Mostly True," both of which include statements deemed at least partly false.
Of course, given that Politifact only looks at statements that arouse suspicion, it's not surprising they'd rate most of them at least a teeny bit false, and by that strict standard, they judged only 25 percent of Clinton's statements, and a pitiful 4 percent of Trump's, to be entirely True.
At the other extreme, they rate 17 percent of Donald Trump's statements false at the Pants-on-Fire level, while a relatively tiny 2 percent of Hillary Clinton's statements are judged that bad.
Quibbling aside, Maher's basic point remains: Trump says things that are demonstrably not true a lot more often than his opponents, both Republican and Democratic.
(Updated 2016 November 6 to correct a couple of typos, add a little additional information, and try to improve the wording in a few spots, I hope.)