Fischer faces state Treasurer Don Stenberg and state Attorney General Jon Bruning in the primary, and the winner will square off with former Sen. Bob Kerrey (D-Neb.) in November. Polling suggests Fischer and Stenberg vying for second place behind Bruning.

"You will go to Washington to serve the people of Nebraska, protect our Constitution and work for common sense solutions to help restore America," Palin said, adding that her PAC would be sending a contribution to Fischer's campaign.