"He's not a person we could trust to lead our country," said Angela Cesar, a 41-year-old Republican from Ypsilanti, Mich., who said Romney had changed his position on too many issues. "He's going to be listening to voices outside. I want someone who can hear his own voice - a clear voice."

Steve Holroyd, a 54-year-old chef from Rye, N.H., was initially attracted to Romney's candidacy, but now describes him as evasive: "The more I listen to him, the more he just kind of flip-flops and doesn't know where he stands on anything."

But it matters to voters like Leonard Silvani, a 58-year-old Republican from Hampton, N.H. Even though he is most concerned about the economy, Silvani said, the shift by Romney on a core issue like abortion is a warning flag.

"It's telling you that what he's saying and what he does aren't necessarily the same thing," he said. "And that makes me leery."