Now that Cranston, R.I., Mayor Stephen Laffey has chosen to buck his party and challenge Sen. Lincoln Chafee (R-R.I.) in the GOP primary next year, Chafee’s colleagues are quickly rallying behind him.

While Chafee has not always been a reliable vote for his leaders, the Senate’s two top Republicans reiterated their support last week.

Senate Majority Whip Mitch McConnell (R-Ky.), who appeared in Rhode Island on Chafee’s behalf in February, huddled with him on the Senate floor Thursday night, shortly after Laffey declared his candidacy.

“Not only am I, but our entire [GOP] Conference is committed to Linc’s re-election,” McConnell said in an interview. “We are going to help him in every way. We have a broad-based party and we are proud of our Northeastern moderates. He is an important part of our team.”

Senate Majority Leader Bill Frist (R-Tenn.) echoed McConnell’s pledge of loyalty.

“I have told Linc I will be supporting him,” Frist said in an interview. “I haven’t seen the primary challenger to evaluate everything, but I told Linc I would be happy to help him out in any way I can.”

Chafee said he he was prepared for Laffey long before Thursday’s announcement.

Unlike many Senators who move their families to the Washington, D.C., area after being elected, Chafee said his wife and children recently moved back to Rhode Island, and acknowledged that the campaign was “a big factor” in that decision. When Senate business does not obligate him to be on Capitol Hill, Chafee is expected to be spending his time crisscrossing the state to meet with voters.

Noting that about only 10 percent of registered voters in the state are Republicans, Chafee conceded that, “Republican primaries are dangerous in Rhode Island.”

As one of the leading centrist Republicans in the Senate, Chafee said part of his strategy would be to try to convince Democrats and politically unaffiliated voters to vote for him in the September GOP primary.

Rhode Island election law allows unaffiliated voters to participate in the primary — they simply must choose one party’s ballot or the other’s. Affiliated voters must either change their party registration or declare themselves independents by June if they wish to participate in the other party’s primary.

“The challenge is getting the unaffiliated,” Chafee said. “And if you have supporters who are Democrats, make sure they disaffiliate 60 days prior to the primary.

“That takes some planning. I certainly will work at finding my supporters in the unaffiliated ranks and making sure they turn out” for the primary, Chafee said.

Sarah Chamberlain Resnick, executive director of the Republican Main Street Partnership, which supports moderate Republicans, called on the Club for Growth, which supports limited government and is considering backing Laffey, to join the Main Street group in supporting Chafee.

Noting that Cranston’s property tax rate has increased significantly under Laffey — The Providence Journal reported that Cranston has one of the highest property tax rates in the state — Resnick said the Club should have no reason to back Laffey.

“The Club for Growth and [President] Pat Toomey made ‘tax hikes vs. tax cuts’ their litmus test for support of any candidate nationwide,” she said. “They ought to stand by that creed.”

Toomey did not respond to Roll Call’s messages by press time Friday. Laffey was nonchalant about whether the Club will back him.

“I have met with the Club for Growth; I haven’t talked to them in many months,” he said Friday. “I have my philosophy. People who agree with my philosophy are ready and welcome to join me.”

Laffey and the group have at least one thing in common: consulting firms. Red Sea in Washington, D.C., has produced numerous ads for the Club for Growth and Toomey in his unsuccessful effort last year to unseat Sen. Arlen Specter in Pennsylvania’s Republican primary. Laffey’s mayoral campaign account paid out almost $13,000 to Red Sea for “research and consulting.”

Laffey said the money was paid from his mayoral account to explore races for state government offices, which is legal under campaign finance laws, not the Senate race, which would not be.

Laffey said he is unconcerned about the Republican Party apparatus being behind Chafee and pledging not to help him should he win the primary. But Laffey said he never considered running as an independent.

Laffey said he is running because he is fed up with Washington’s “special interests” calling the shots, and because he is a financial expert who can straighten out the nation’s budget deficit.

“I’m running for the United States Senate because the smallest state in the Union needs the strongest voice in the Senate: to fight the big drug companies; to fight the other special interests that have corrupted our tax code and have hurt the hardworking taxpayers of Rhode Island,” he said in his speech at the Cranston Knights of Columbus on Thursday night.

But why knock off Chafee, who is seen by national GOP leaders as the only Republican who can hold the Senate seat in a heavily Democratic state?

“Linc Chafee is a nice man, I like him on a personal level,” Laffey said. “The problem is that Washington is now run by the special interests … and he’s not standing up for Rhode Island.”

Laffey also disputed the conventional wisdom that he will be buried financially by the national GOP and Chafee’s personal wealth.

He noted that his background as an investment banker shows he knows how to raise capital, and said he can contribute to his own campaign as well.“I will put in the amount of money and loan the amount of money to my campaign that is appropriate, that shows everybody that I got my skin in the game.”