Why can't we say it? (No, not *that* word)
I mean this one: "Lie" as in "untruth."
We journalists are loathe to say a politician is lying.
Let's take that Bridge to Nowhere. Sarah Palin repeatedly says on the stump, "I said 'thanks, but no thanks' to the Bridge to Nowhere." And yet nearly every news outlet has repeatedly said that's not true; she was for it before Congress withdrew the funding for it.
News organizations often say a politician is "exaggerating" or "mis-stating." We don't use the word "lying" because it implies intent to deceive.
We didn't use the L word during Hillary Clinton's, um, forgetfulness regarding taking cover under Bosnian sniper fire.
We didn't use it when Bill Clinton was parsing the word "is."
And we're not using it now...Yet...