MANCHESTER, N.H. — Roy Barbuto is on the hunt. For the past few months, he has been searching for the perfect Republican candidate, and he shows no signs of flagging.

Mr. Barbuto, 61, a service technician here, had already seen Representative Michele Bachmann of Minnesota (“She was excellent”), the former pizza executive Herman Cain (“He intrigues me, because here is a man who clearly knows what to do businesswise”) and former Gov. Mitt Romney of Massachusetts (“If he was elected, he could certainly do the job”). Now, he was finishing up dinner at a house party in Chichester, N.H., waiting to take a measure of Gov. Rick Perry of Texas.

“I’m not just looking for a candidate to beat the president,” he explained. “For me, the purpose of the next president is to restore the pride that this country has always had.”

In interviews with more than two dozen people in New Hampshire and Iowa over the Labor Day weekend, voters said they sensed a new vulnerability to President Obama.