The announcement yesterday from Republican gubernatorial candidate Peter Cianchette that he was quitting the race after being in it for only a couple of months was both a surprise and an opportunity for the GOP. The party has grown stronger in recent years not because it has moved farther to the right politically but because its organization has improved even as it has maintained its place in the mainstream.

After a close finish against John Baldacci in the 2002 gubernatorial race, Mr. Cianchette, a former legislator who is well known in much of Maine, was the expected candidate in 2006 of many though certainly not all party members. He had three years to think about the next race and get his organization together. So certain were some of his general-election candidacy, when Mr. Cianchette announced his decision to run in July, former member of Congress David Emery immediately dropped out of the primary race. Polls showed Mr. Cianchette running strongly against the governor.

His departure now comes with barely an explanation – essentially he says he wants to spend more time with his family, that he was “blind to what is most important to me at this time – being totally present and available to be with family.” Barring other personal reasons, that sounds like a candidate who discovered too late just how grueling a campaign is.

Nevertheless, the race is now wide open, and should remain open enough to accept this insight for the value it contains: “In Maine, if you’ve got the right wing angry at you, then you’re going to win the general election with 60 percent of the vote. It’s when the right wing agrees with you that you’ve got trouble.” Christian Potholm, a Bowdoin College government professor and Republican political consultant, told the Boston Phoenix newspaper that several years ago, and it remains true today. If a Republican is going to live in the Blaine House in January 2007, that candidate must appeal to the large number of unenrolled voters who occupy the center of the political spectrum.

State Sen. Peter Mills, the other announced GOP candidate, certainly fits that description, though he certainly will see other candidates who had been staying out of the race now eager to jump in. A vigorous primary, in fact, is the best thing Republicans could hope for, to test ideas and to increase the name recognition of their candidates.

With their front-runner gone, the party should be in pursuit of moderates who can challenge the governor on issues and attract voters from the center.