Republican Sen. Lincoln Chafee picked his way among the picnic tables beside Mishnock Pond yesterday afternoon, grabbing hands as if they were lifelines.

Chafee is fighting a conservative primary challenger, and the results tomorrow not only will help determine whether Democrats have a chance of taking back the Senate but also will speak volumes about the fate of the GOP's endangered moderates.

"I need your vote Tuesday," Chafee said as he greeted Nelson Reynolds at a Lions Club steak fry. "I'm working hard for you."

"You'll get it," said Reynolds, 65, a painting contractor.

Rhode Island, the smallest state, has been swamped by about $5 million worth of television advertising - much of it negative - in a replay of the right's attempt two years ago to knock off Sen. Arlen Specter (R., Pa.). Some also see reflections of Democratic Sen. Joseph I. Lieberman's loss last month in the Connecticut primary, and worry about another potential milestone in the polarization of U.S. politics.

Lieberman ran afoul of liberal activists largely for his support of the Iraq war. Chafee is in the crosshairs of the Club for Growth, an antitax group whose president, former U.S. Rep. Pat Toomey, nearly defeated Specter in the 2004 Pennsylvania GOP primary.

Chafee's perceived ideological sins are manifold. The son of a former governor and senator, and a descendant of one of Rhode Island's founding families, Chafee has broken with his party and President Bush on tax cuts, judicial nominations and environmental issues, and was the only Republican to vote against authorizing the Iraq war.

The challenger, Cranston Mayor Stephen Laffey, 43, is a former stockbroker who opposes abortion rights and embryonic stem-cell research, and supports the war. But his campaign has been mostly a populist rant against "insiders" like Chafee. He also has bashed oil companies for high gasoline prices and says Bush has failed on energy policy.

Toomey's Club for Growth has raised or given, through its political action committee, $1.2 million to Laffey. Several of Specter's advisers, including adman Chris Mottola, are working with Chafee.

"It's the same thing I faced," Specter said. "They're demanding ideological purity... . The Reagan 'big tent' that has been the dominant approach of the party for the last generation - they just categorically reject it in favor of 'rule or ruin.'"

Toomey said Chafee does not appeal to Republicans who are interested in pro-growth policies.

"Having Lincoln Chafee is like having a Democrat anyway," he said. "He votes for the Democrats on almost everything all the time."

But the national Republican Party has rallied around its most prominent rebel, sending get-out-the-vote experts to the state. If Chafee loses, the National Republican Senatorial Campaign Committee has said it will pull out of Rhode Island.

"It's a double-edged sword," Chafee said of the national backing, adding that he needed Democratic-leaning unaffiliated voters to cast ballots in the GOP primary. Only 11 percent of Rhode Island voters - or around 70,000 people - are registered Republicans, but independents can participate in either primary.

"My chances are much, much greater in the fall in this most Democratic of states," said Chafee, who is nearing the end of his first full term. "I think Americans are so tired of polarization in their politics that they want somebody in the middle."

Polls have shown Laffey trailing Democratic nominee Sheldon Whitehouse, a former Rhode Island attorney general, by 30 percentage points, and that Chafee could beat him.

"I'll crush him [Whitehouse]," Laffey said, pausing after powering through the crowd at a dragon-boat contest in Pawtucket on Saturday. "Whitehouse is the same thing as Chafee; they think they were bred to be in charge. These people have zero in common with the state's voters."

Laffey said he understood the struggles of average people, since he is the son of a toolmaker and a nurse, the first in his family to go to college.

Chafee has been "irrelevant" in Washington because of his zig-zag voting pattern, Laffey said, sneering at the national Republican establishment.

"They're hypocritical," he said. "Their message is, 'Vote for the guy who opposed the tax cuts, who voted against [Supreme Court Justice Samuel] Alito.' It's all about power."

And they are fighting hard to keep it. Recent ads from the Chafee campaign have pounded Laffey as a "tax and spend" mayor because he raised taxes to keep Cranston out of bankruptcy, and other ads attack his personality - one, called "Bully," shows him appearing to go after a firefighter during a heated discussion in a city council meeting. Still another ad, from a group called Republicans Who Care, cites a lawsuit by a former employer that accused Laffey of stealing confidential data.

On the other side, Club for Growth ads blast Chafee for voting for the infamous "bridge to nowhere" in Alaska in last year's highway appropriations bill. And in the last few days, people have been reporting a "push poll," in which callers give Chafee supporters a graphic description of the late-term procedure opponents call "partial birth" abortion.

"This is not like any primary we've ever seen," said Victor Profughi, a pollster at Rhode Island College. Poll results are contradictory and "nobody knows for sure" because it is hard to guess how many independents will participate, he said.

The biggest GOP primary, for the 1994 gubernatorial contest, drew just 45,000 voters.

"No one really dislikes Chafee, and it's tough for me not to vote for him again, but things just need to be changed," said Donna Barrett, an unaffiliated voter from Warwick who liked Laffey's energy when he visited her neighborhood last week.

Frank "Butch" Keenan, enjoying the country music at the steak fry, said he was going to vote for Chafee.

"He's one of the honestest guys in Washington, possibly the only one," said Keenan, 65, a Republican who owns a fence company. "He does his own thing, for the people, not the party. You've got to have that."