Republicans united solidly behind Peter Cianchette Tuesday, choosing the 40-year-old business consultant as the party’s best hope to become Maine’s next governor.

The former South Portland legislator continued to outpace his opponent, James Libby of Buxton, by a 2-1 margin for most of the evening. Shortly after 11 p.m., Libby conceded the race and pledged to support Cianchette.

“I think the vote says a lot about his organization,” Libby told reporters gathered at his Falmouth reception. “Well, congratulations to him.”

In a victory speech at the Regency Hotel in Portland, Cianchette thanked his staff, supporters and his primary opponent and sent a televised message to John Baldacci, the Bangor Democrat who won his party’s nomination in an unopposed bid.

“The coronation has been canceled and the race starts now,” Cianchette said.

Cianchette urged all Maine Republicans to start working now to win the general election on Nov. 5. Then he reached out to Libby’s supporters and asked them to get behind his campaign.

“United, I know we can be successful,” Cianchette said.

In a telephone interview shortly before 11:30 p.m., Libby said he was genuinely impressed with the depth of Cianchette’s support and said the primary winner could count on him all the way to the Blaine House.

“We have platforms that are similar and I know we’re dedicated to the same goals,” Libby said. “He’s proven that he got the support he needs statewide and he’s got my support – 100 percent.”

In unofficial returns representing 86 percent of Maine’s 659 precincts, Cianchette outpaced Libby 43,709 to 21,930. The GOP primary winner will advance to the general election to compete on a crowded gubernatorial ballot against Baldacci; Jonathan Carter, the Green Independent Party candidate from Lexington Township; David Flanagan, a Manchester independent; and John Michael, an independent candidate from Auburn.

As Maine’s voting centers closed at 8 p.m., it became clear that pollsters’ predictions of a statewide turnout of about 25 percent might have been high. With 72 percent of precincts reporting, the turnout was at about 20 percent.

As a group, Republicans account for a little less than 29 percent of all registered voters in Maine. About 146,000 live in the state’s southern 1st Congressional District, while an estimated 126,450 live in the 2nd District.

Unlike the 1st District or the U.S. Senate race, where there was no contested primary for either party, the 2nd District featured a competitive four-man contest for the vacancy created by Baldacci’s decision to retire after four terms in Congress.

But the level of Republican voter activity was not expected to dramatically enhance the chances of one gubernatorial candidate over the other, according to MaryEllen FitzGerald, a politically independent pollster who runs Critical Insights in Portland. Instead, she said, Maine Republicans were more focused on the candidates’ messages. FitzGerald said Cianchette’s simple pledge of less state spending, more jobs, and economic expansion was exactly what GOP voters wanted to hear.

“The question for Republicans was the economy, and that was Cianchette’s message from the very onset of his campaign,” she said.

Still, the positions of Cianchette, a businessman-turned-consultant, and of Libby, a 41-year-old high school teacher, have remained almost indistinguishable on many key issues. They both oppose late-term abortions, but do not favor overturning the U.S. Supreme Court decision that legalized abortion on demand. Both would continue to extend a state spending freeze and both oppose tax increases as solutions to the state government’s recurring budget shortfalls.

Both oppose casino gambling, a single-payer health care insurance system, and a North Woods national park, and both support increased state reimbursement to communities for educational costs and favor income tax reductions.

Among areas of disagreement, Cianchette favors gay rights, supports enterprise zones to stimulate targeted areas of expansion for economic growth, and is undecided about a plan to transform the state’s technical colleges into community colleges. Libby opposes his opponent’s positions on gay rights and enterprise zones. He also supports term limits and public financing for political campaigns, which gave him $328,000 for his primary bid. Cianchette, who privately raised more than $435,000 as of May 30, is opposed to both laws.

Where both men differ most is in areas of personal campaign styles, messages and backgrounds. While each has legislative experience, Cianchette was already well known in state political circles by the time he reached the State House as a freshman legislator. The son of a founder of the Cianbro Corp., one of New England’s largest construction companies and based in Pittsfield, Cianchette managed a cement company and his own employment agency before throwing his hat into the political ring for governor. He also made the rounds of Maine’s Republican inner circle to lock up a significant percentage of political and fund-raising support before even making his first gubernatorial campaign speech.

By contrast, Libby took on the daunting task of running as a publicly funded candidate under Maine’s Clean Election Act and exceeded the threshold requirement of securing 2,500 signatures and individual $5 checks to qualify under the law. If Cianchette was the party’s mainstream candidate, Libby chose to portray himself as the party’s grass roots choice – implying a populist appeal that would transcend party lines and attract many of the state’s unenrolled voters, who make up nearly 39 percent of all registered voters, for the November general election.

Libby, a teacher, was required to be in school for much of each day leading up to Tuesday’s election, limiting his opportunities for travel and speaking engagements. He chose to make expanded educational opportunities and increased access to health insurance the centerpieces of his campaign. He also actively sought to align himself with some of the party’s more conservative elements to reinforce the perception that he was farther right than his opponent.

Cianchette was free to travel and made more appearances statewide than Libby. Although he addressed other issues, Cianchette hammered away on the state’s economy and the creation of new jobs as the principal themes of his campaign. In keeping with the entrenched traditions of U.S. Sens. Olympia J. Snowe and Susan M. Collins, Cianchette sought to characterize himself as a political moderate who would be more inclusive than Libby when attempting to lure Democrats and independent voters in November.