The quarrel over Politifact's "Lie of the Year" is missing the point. The fact-checker gave its annual accolade to the Democrats' claim that Paul Ryan's budget plan would "end Medicare". Liberals are rightly annoyed. Paul Krugman says Politifact is dead to him: guilty of False Balance, a capital crime. He reckons their calculation was obvious. Politifact's previous Lies of the Year were Republican lies: facts be damned, it was time for a Democratic winner.
As you know I rarely agree with Krugman about balance--in my world, balanced is better than unbalanced--but I bet Krugman is right about Politifact's thinking. The claim that the Ryan plan would "end Medicare" is at least defensible, and nobody denies that the plan would end Medicare as we know it (that's the idea). But the main thing here is that, whether they realize it or not, Politifact and the other fact-checking outfits rarely confine themselves to checking facts. They're judging claims purportedly based on facts, or interpretations of facts. Not the same.
The giveaway is their grading system. You check a fact by asking whether it is true or false. If true or false is not good enough to assess the thing you are checking, then the thing you are checking is not a fact. Politifact has a six-point grading system: true, mostly true, half true, mostly false, false, and pants on fire. These are grades you might apply to bundles of facts or claims based (with more or less validity) on bundles of facts, but not to facts.