A new USA Today/Gallup poll finds that 51% of Americans have never heard of McCain’s running mate.

Only 39% say she is ready to be president, if needed– the lowest proportion since Dan Quayle in 1988. 33% say she is not ready, and 29% have no opinion.

Two of three say Palin will have no impact on their vote.

Conducted Friday; Error margin: 4 points.