"Pryor, 49, of Norman said party workers are trying to make sure Democrats who vote only in presidential election years get out to vote this year and to persuade registered Democrats who have been voting Republican to return to their party."
First of all, the "of Norman" should be in a different sentence. Choose either the "49," (*does it matter how old the chair of a state political party is??) or the "of Norman," but not both. Second, "party workers," the predicate noun, is followed by the two verb phrases: "are trying to make sure" and "[are trying] to persuade." But there is too much info between these phrases and the "to persuade" seems to come out of nowhere.
This has not been my most eloquent grammar explanation but it's sunday morning and I'm tired.