Yes. It is assault.
EDIT: Misplaced, you are the idiot. First of all, a police officer will not stand in front of the polling place and tell you that you can't vote. They are there to enforce the law, not to violate it. Secondly, go ahead and spit on a peace officer. Then you just graduated from assault, which is a misdemeanor, to exposing a public official to bodily fluids, which is a felony.