Facts are not always black and white, meaning true or false. Some times there are nuances that result in silliness like quibbling over the meaning of 'is.' That's politician crap for "I'm thinking, just let me sit here and think a spell. My answer needs thinking about."
On the other hand, I will be glad for the day when a politician who is being lied about and smeared (say, Barack Obama), stands up and says, "He (or she) is lying." Straight out calling a prevaricating, disassembling, factually incorrect, misinterpreting of the truth opponent, the lying weasel that he or she is, would feel satisfying. But the word liar seems impossible to utter. Why?
I don't want any politically correct words any more. If Palin's LYING, and I believe she is because she is a politician, then SAY SO! Don't induce grey where black and white exists. IF a Fox news personality is talking, they are lying. It's endemic at that organization. SAY SO!
Obama's said "ENOUGH!" Now it is time to use that other fightin' word.