INDIANOLA, Iowa (AP) - Michele Bachmann's struggling presidential campaign has been dealt another setback: One of her Iowa co-chairmen has defected to rival Ron Paul's side.

Hours after appearing with Bachmann at a Wednesday event, state Sen. Kent Sorenson gave his endorsement to the Texas congressman at a Des Moines rally. Sorenson said he resigned from Bachmann's campaign to join the most conservative of the top-tier candidates.

The Minnesota congresswoman has been unable to recover from a fall slide that followed her Iowa straw poll victory in August. Paul was a close second.

Sorenson has strong ties to Iowa's tea party, and he joined her for an afternoon stop on her 99-county tour. He didn't speak at that gathering, citing recent dental work.

Bachmann criticizes Paul as "dangerous" for his hands-off foreign policy.