STRATHAM, New Hampshire (CNN) - Mitt Romney has been shifting his message to focus on change following the emergence of Barack Obama as the Democratic frontrunner.
Romney said Republicans need a nominee who can compete with Obama.
"I think Republican voters who, like myself, were virtually certain that Hillary Clinton would be the nominee have now begun to rethink Hillary Clinton may not be the nominee," Romney told reporters here.
He said Obama's message of change has "put Hillary Clinton on her heels" and that if the Illinois senator becomes the nominee, then Romney's rival Sen. John McCain will be the wrong standard-bearer for Republicans.
"Frankly, I don't think Senator McCain, despite his service and his length of experience that that's going to be able to stand up to the message that Barack Obama has brought forward," he said.
"We better think about somebody who can stand up with a message and go toe to toe with [Obama]," Romney said, adding that he can "post up against" Obama.
Romney senior adviser Ron Kaufman said Obama " demolished three senators in Iowa" and will "demolish" Clinton in New Hampshire, "so clearly having a senator against him is not a good idea."
- CNN Political Producer Peter Hamby