PROVIDENCE — A surge of newly registered Rhode Island voters — many of them young — looms as a decisive force in the March 4 presidential primary, especially in the tight Democratic contest between New York Sen. Hillary Rodham Clinton and Illinois Sen. Barack Obama.

More than 43,000 voters signed up over the last year, with about half of those (21,000) coming in the four months before the Feb. 2 deadline to register for the March vote, according to a Journal analysis of state voter files.

Of those 43,000, roughly 20,000 are between the ages of 18 and 29, a group once derided as stay-at-homes on election days, but since 2004 a group that has been casting ballots in increasing numbers.

Those new registrations are a vast increase over the numbers in 1992, 1996, 2000 and 2004, all presidential election years. For example, in the four months before the 2004 state presidential primary cycle, about 12,400 new voters were enrolled in the state, compared to roughly 21,000 in the four months that ended this Feb. 2.

New voters have never before been a foundation of a presidential primary victory in Rhode Island, a state where the contest was always held after both the Republican and Democratic presidential races have been largely settled.

This year, Rhode Island — at least on the Democratic side — is fiercely in play. The Obama and Clinton campaigns are advertising on local television stations, and both campaigns are preparing vigorous voter-turnout efforts.

In terms of putting together a get-out-the vote organization, Obama got a head start on Clinton in Rhode Island. Obama’s state director is Mike Dorsey, who spearheaded the 2006 turnout campaign for the state Democratic Party and Sen. Sheldon Whitehouse. But the Clinton campaign announced yesterday that she will stump here on Feb. 24, probably in the Providence area; Obama has yet to make a commitment to campaign here.

A Brown University public-opinion survey put Clinton’s lead over Obama at 8 percent, with a large pool of undecided voters. The poll carried an error margin of about 4 percent.

Both campaigns are making a push starting today for volunteers to help contact voters. On the Republican side, Arizona Sen. John McCain, the presumptive GOP nominee, campaigned in Warwick on Thursday. He has only Mike Huckabee, the former Arkansas governor, and U.S. Rep. Ron Paul, of Texas, left as rivals in the contest. Neither Paul nor Huckabee has generated much traction in Rhode Island, while McCain has the endorsement of the state GOP establishment.

Independents can vote in either presidential primary. Of the last four months of voter signups, about 6,800 enrolled as Democrats, roughly 1,900 became Republicans and more than 12,000 registered as independents, a category deemed “unaffiliated” in state political argot.

Another New England state, Vermont, votes on the same day as Rhode Island. Two bigger states, Ohio and Texas, also hold primaries on March 4.

Rhode Island’s recent experience with young voters mirrors what has been happening around the country, says John Della Volpe, director of polling at the Institute of Politics at the John F. Kennedy School of Government at Harvard University.

“This is not a one-time spike; this is the third straight year of increased registration,” says Della Volpe. He attributes some of the surge to the 9/11 terror attacks. “Before that, young people didn’t think their votes mattered; they thought all politicians were the same.

“Now, politics is about major, life-and-death issues, the war, globalization and climate change,” said Della Volpe.

Obama’s campaign, Della Volpe says, was a factor in the big increase in voter turnout in the early Democratic caucuses and primaries. “Obama kind of lit the fire. I do think young people are going to vote this year regardless of Obama.

“What he did that was significant was to make young people his focus, and he won the Iowa caucuses with a 5-to-1 margin among voters under 35,” said Della Volpe. “Hillary has gotten the message and now she is talking to young people.”

Those who teach college students in Rhode Island say today’s students take civic participation, politics and voting seriously. “Young people feel empowered in ways they didn’t feel in the 1990s,” says Wendy Schiller, a political science professor at Brown University.

“At campuses like Brown, [Providence College] and [the Rhode Island School of Design], they tend to be more liberal and they tend to vote Democratic,” says Schiller.

Part of the increase in young voter registrations is due to population trends and demographics, say Della Volpe and Schiller. “You have a historic bulge of college students: the children of the baby boomers are coming to campus, and last year had more people going to college than ever, and it is only going to rise over the next few years,” says Schiller.

At the University of Rhode Island’s Kingston campus, political-science Prof. Maureen Moakley says her students are “very engaged” this year in the presidential campaign.

“I am amazed at the level of enthusiasm among my students for Barack Obama,” says Moakley. “The question is how many of these young people will turn out to vote. But just the fact that they have taken time to register suggests that something is out there is driving this.”

Rhode Island’s primary has long been derided as the orphan child of American politics, known chiefly for having the lowest turnout in the nation. One reason is that no other local elections or issues are decided that day; the day is reserved for presidential primary voting.

Massachusetts Sen. John Kerry swept to victory in the state in 2004, drawing just 14,540 votes in the 1st Congressional District and 10,926 in the 2nd District. In 2000, Vice President Al Gore received 26,801 votes statewide, and former New Jersey senator Sen. Bill Bradley got 19,000.

There have been earlier jumps in younger people voting, particularly in 1972, the first year the eligible age was lowered from 21 to 18 and former South Dakota Sen. George McGovern’s antiwar presidential campaign drew the young into politics. In 1992, a three-way race for president, with voters choosing among Democrat Bill Clinton, Republican George H.W. Bush and independent Ross Perot also drew voters new to politics.

“This is an exciting year in Rhode Island,” said Moakley. “It’s like we are Iowa or New Hampshire.”

smackay@projo.com