Resurgent Romney is the Maine man

But the former Massachusetts governor's margin of victory over Texas Representative Ron Paul was so slim it all but guaranteed scrutiny of the party's decision not to count the results of caucuses scheduled later in February.

The Maine victory comes at a critical time in Mr Romney's quest to become the Republican nominee who will take on President Barack Obama.

Mr Romney is working to gain trust from the conservative activists who make up the Republican base and who drive the party's nominating contests in the state-by-state contests to choose delegates to the party's national convention in late August in Tampa, Florida. They view him sceptically because of his past shifts on a variety of issues, including his previous support for abortion.

On Friday, Mr Romney delivered a high-profile address to a Washington meeting of conservative activists in which he described himself as "a severely conservative Republican governor".

The speech represented a full-throated insistence that he is conservative in both record and background, a message he sought to send as he worked to convince the party's sceptical right flank that he is acceptable as the party's nominee. "My path to conservatism came from my family, from my faith and from my life's work," Mr Romney said.

At a state party gathering in Portland, state Republican chairman Charlie Webster announced Mr Romney had won with 2,190 votes compared to 1,996 for Mr Paul, the only other candidate to aggressively compete in the state. Former Pennsylvania Senator Rick Santorum received 989 votes and Newt Gingrich, the former speaker of the House of Representatives, won 349, but neither actively campaigned there.

Mr Webster said any caucus results that come in after Saturday would not be counted no matter how close the vote turned out to be.

Maine's caucuses began on February 4 and continued throughout the week. But the results accounted for just 84% of all precincts in the state. Several communities elected to hold their caucuses at a later date.

Caucuses in Washington County were postponed until February 18 because of a major snowstorm that blanketed the region. Earlier, the state party's executive director Michael Quatrano said county officials were told the results would not count toward the total.