COLUMBUS, Ohio (AP) — Mitt Romney and running mate Paul Ryan look to shrug off the latest in a series of unwanted distractions when they face Ohio voters as the Republican presidential ticket for the first time.

The two men are appearing at a Columbus-area rally Saturday morning, less than 24 hours after Romney raised the discredited rumor that President Barack Obama wasn't born in the United States. The comment, and his efforts to explain it, overshadowed Romney's economic message as he campaigned near his Michigan birthplace on Friday.

At the same time, Obama is launching a new Medicare offensive using his radio and Internet address and a new campaign ad to help highlight Romney's plans for the health care program for seniors.