PROVIDENCE -- After a campaign for the ages, the close and bitter Republican U.S. Senate primary between Sen. Lincoln Chafee and Cranston Mayor Stephen Laffey boils down to which campaign can best perform that oldest of political chores -- getting their supporters to the polls.

As the hours dwindle to Tuesday's election, the weapons are the telephone, the knock on the door, the leaflet dropped at the front door -- and the outstretched hands of the candidates.

Both Chafee and Laffey will be traveling the state this weekend in a frenetic blur of eleventh-hour stumping. Chafee, facing the strongest renomination challenge any incumbent Rhode Island senator has faced since the state's modern primary system began, in 1948, will have help from hundreds of volunteers blanketing the state, said Ian Lang, the senator's campaign manager.

Laffey's spokeswoman, Nachama Soloveichik acknowledged the mayor's get-out-the-vote effort would include telephone and direct-mail pitches, but declined any further comment.

Chafee is being attacked at the last-minute by a series of nasty push-poll phone calls by anti-abortion and anti-gay rights groups from Ohio. One of the calls includes a graphic description of a so-called late-term abortion.

"We've had a lot of negative reactions to these push-poll tactics," Lang says. "We think they are backfiring."

Laffey's campaign has disavowed any knowledge of the push polls, which are illegal in some states, though not in Rhode Island.

Just about everyone who studies or works in politics in Rhode Island thinks the election will go down to the wire and will attract droves of voters.

"I believe this will be the highest Republican primary turnout in the history of the state," says Maureen Moakley, chairwoman of the political science department at the University of Rhode Island. "I think the amount of money that has been spent, all the national attention and the high-profile campaigns by Chafee and Laffey will increase turnout."

The previous modern GOP record primary turnout came in 1994, when 45,023 voters participated in the gubenatorial primary between then-U.S. Rep. Ronald Machtley and then-U.S. Attorney Lincoln Almond. Almond won and went on to win two terms in the State House.

Rhode Island has a hybrid primary, meaning independents -- technically called unaffiliated voters -- can vote in either the Republican or Democratic primary. Registered Republicans are limited to voting in the GOP primary, and enrolled Democrats can cast ballots only in their party's primary.

There are 365,658 independents eligible to vote in either primary, 68,864 Republican voters who cast only GOP ballots, and 236,665 Democrats who can vote only in their party's primary.

An intriguing subplot to Tuesday's election are the roles played by Cranston and Warwick, the two communities that grew greatly after World War II when the children of immigrants raised in triple deckers in city neighborhoods moved to single-family houses in green-lawned suburban developments.

The Cranston-versus-Warwick angle plays to each candidate's voter base. Chafee was a popular Warwick mayor until he became senator upon his father's death, in 1999. Laffey is a popular Cranston mayor who crushed his 2004 GOP primary opponent.

In the 1994 record-GOP-turnout election, roughly 9 percent of the votes came from Cranston and 9 percent from Warwick. (Almond carried both communities comfortably.)

Warwick Mayor Scott Avedisian, who has been working hard for Chafee, estimates that about 6,000 city voters will turn out Tuesday, which he says will favor Chafee. So far, more than 200 absentee ballots have been requested in Warwick, Avedesian says, which compares with between 25 to 30 for a typical municipal GOP primary.

The other element helping Chafee is that there are not competitive local Democratic primaries to draw voters away from the GOP contest, except that a Warwick native, Democratic U.S. Rep. James Langevin, has a primary opponent in Jennifer Lawless, a Brown University professor and political newcomer. But with Langevin heavily favored, Chafee's camp believes the senator will capture a big segment of independent voters.

Laffey has proven that he can push voters to Cranston polls. He won nearly 8,000 votes in his 2004 primary, a city record. A relentless door-to-door campaigner, Laffey also easily defeated a Democratic challenger in 2004.

But Cranston has some Democratic primaries, including a mayoral primary, races for state representative and City Council, and a competitive election for the state Senate seat being vacated by Sen. Elizabeth Roberts in a district anchored by the Edgewood neighborhood.

"Cranston and Warwick are so important because both candidates and their campaigns know personally who their voters are," says Joseph Fleming, Channel 12 pollster and political analyst.

Other areas to watch closely Tuesday are the east side of Narragansett Bay and the rural communities of South County and western Rhode Island. Laffey is expected to do well in such areas as Charlestown, Exeter, West Greenwich, Burrillville, Foster and Glocester.

"Those little communities usually aren't crucial in a statewide Republican primary but they probably will be in this election," Fleming says.

On the Chafee side, even his campaign officials acknowledge that it will be difficult for him to prevail without strong showings in the ribbon of East Bay communities from East Providence's Rumford neighborhood through Barrington, and Bristol, and into Portsmouth, Middletown and Newport.

Providence, the state's largest city, is not as important in Republican primaries as suburban areas, but Chafee campaign manger Lang says their camp hopes to pick up votes on the affluent East Side, a onetime GOP stronghold that has trended Democratic in recent years.

The problem with that strategy is that parts of that neighborhood have a spirited Democratic City Council contest between incumbent Rita Williams and her challenger, Cliff Wood.

The irony is that there are lawns on the East Side sprouting both the familiar blue-and-green "Keep Chafee" signs and "Cliff Wood" placards. Unaffiliated voters cannot support both of those candidates; they must, of course, choose either the Democratic or Republican primaries.

"I think in the end it is going to be the independent voters who decide this election," says Darrell West, Brown University political science professor and pollster.

smackay@projo.com / (401) 277-7321