Every so often, some public official tells such a blatant lie that even the lapdog news media feel obliged to point it out. One thing they never do, though, is come right out and call the liars what they are: liars. Okay, every so often we can accept that somebody might "misspeak" — but when somebody tells a straight-out pants-on-fire whopper, I don't think liar is too strong a term.
In yesterday's Times, for example, there was a well-reasoned and well-documented article about New Jersey governor Chris Christie, documenting how he repeatedly delivers misinformation (also called lies) to the public and the press. Not once, of course, did the Times use the plain English word "liar" with respect to the governor. One supposes the editors are sensitive to accusations of liberal bias, but the accusations will come anyway — especially from those who want the public to go on believing Christie's lies.
Of course, New Jersey Democrats also refrain from calling Christie a liar. Granted, New Jersey politicians of both parties are not exactly renowned for their scrupulous veracity, and sometimes it surely would be a case of "the pot calling the kettle black." You might think a good defense against that might be honesty, but you'd be wrong. Liars have no compunctions about lying to claim that truths are lies and lies are truths.
On the other hand, the secret of Christie's success — and that of most other political liars as well — lies in his very aggressive stance towards his opponents. He doesn't even have to answer questions or criticisms to satisfy the voters, as long as he stays on the attack. A successful counterattack has to be equally aggressive, and the consistent use of a term like "liar" will do the trick — whether he's genuinely lying, merely mistaken, or just spouting ideological sound bites that can be neither confirmed nor disconfirmed.
It's not realistic to expect everybody to use factcheck.org or some similar service. Realists must assume that people believe whatever fits best with their pre-existing beliefs and prejudices. Come to think of it, when you consider that most Americans think the vast majority of politicians are liars, it is not surprising that verified facts play such a small part in our political discourse.