You may not say what you mean, but darn it, mean what you say!
Politics is politics, and oftentimes the guy in the limelight with a dozen microphones in his face can't always say exactly what he thinks... unless you're Joe Biden and throw the consequences to the wind. But for all our sakes, if you're going to say something, but better know what you're saying.
Republican Senator Jon Kyl should have thought twice about using poll numbers by CNN... when talking to CNN. Especially when it's Wolf Blitzer on the other side of the line. When you use poll numbers as the basis for your argument, you sign up to having poll numbers used as the same qualifying criterion.
And when someone calls you out on this, you can't just say now you don't believe the numbers. At the end of the day, everyone has to play by the rules - at the very least the rules you yourself make up.