(CNN) - Barack Obama's name is likely to help several Democratic candidates down ballot, but what about a Republican?
Oregon Sen. Gordon Smith, one of the most vulnerable Senate Republicans, is stressing his history of working with the presumptive Democratic nominee in a new campaign ad hitting airwaves Tuesday.
"Who said Gordon Smith helped lead the fight for better gas mileage and a cleaner environment? Barack Obama," the ad's narrator states. "He joined with Gordon and broke through a 20 year deadlock to pass new laws which increased gas mileage for automobiles."
The Obama campaign immediately made clear the Illinois senator is supporting Smith's Democratic opponent.
“Barack Obama has a long record of bipartisan accomplishment and we appreciate that it is respected by his Democratic and Republican colleagues in the Senate," Obama spokesman Bill Burton said. "But in this race, Oregonians should know that Barack Obama supports Jeff Merkley for Senate. Merkley will help Obama bring about the fundamental change we need in Washington."