Romney visited two caucus sites Saturday after abandoning plans to take the day off. The change made clear that his campaign could ill-afford another loss.
Romney also held a town hall-style meeting in Maine on Friday night. It was the first time he'd taken voter questions since campaigning in South Carolina last month.
Maine's nonbinding presidential straw poll had drawn virtually none of the hype surrounding recent contests in Florida and Nevada, where candidates poured millions of dollars into television and radio advertising.
Romney's campaign had placed only a small cable television ad buy airing Friday and Saturday, at a cost of several thousand dollars. But he sent surrogates to the state in recent days and hosted a telephone town hall in addition to Friday's campaign stop.
Romney consistently declined to criticize Paul, however.
Instead, he lobbed indirect criticism at Santorum, a former Pennsylvania senator, and Gingrich, a former House speaker, by repeating intensifying rhetoric of recent days that paints them as tainted Washington insiders.
"I have never spent a day in Washington working," Romney said. "I expect to go there, get it fixed and then go home."
He added, "In my home with my mom and dad I learned conservative values. In my faith I learned conservative values. And in my business."
Romney won 11 delegates in Maine and Texas Rep. Ron Paul won 10, according to an analysis by The Associated Press. Former Pennsylvania Sen. Rick Santorum and former House Speaker Newt Gingrich were shut out.
Fouhy reported from Washington. Associated Press writers David Sharp in Portland, Maine, and Glenn Adams in Augusta, Maine, contributed to this report.
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