McCain and Palin are spewing straw man arguments.
A straw man argument is an informal fallacy based on misrepresentation of an opponent's position. To "set up a straw man," one describes a position that superficially resembles an opponent's actual view, yet is easier to refute. Then, one attributes that position to the opponent. For example, someone might deliberately overstate the opponent's position. While a straw man argument may work as a rhetorical technique--and succeed in persuading people--it carries little or no real evidential weight, since the opponent's actual argument has not been refuted.
Its name is derived from the practice of using straw men in combat training. In such training, a scarecrow is made in the image of the enemy with the single intent of attacking it. Such a target is, naturally, immobile and does not fight back, and is not a realistic test of skill compared to a live and armed opponent. It is occasionally called a straw dog fallacy, scarecrow argument, or wooden dummy argument. In the UK, it is sometimes called Aunt Sally, with reference to a traditional fairground game.