In this Aug. 3, 2012, file photo, Indiana Gov. Mitch Daniels, left, chats with Rep. Joe Donnelly, D-Ind., at the Indiana Pork Producers Ham Breakfast at the Indiana State Fair in Indianapolis. Donnelly is running for the U.S. Senate seat against Republican Richard Mourdock. Senate Republicans are jumping into Indiana's Senate race with a new ad, outdoing a recent buy from national Democrats as the parties battle for control of the Senate. Spending in Indiana has quickly escalated as Donnelly has stayed neck and neck with Republican Richard Mourdock since May. Mourdock's primary victory over Sen. Richard Lugar created the opening for Democrats in Indiana.