PROVIDENCE — Known for years as the afterthought of American politics, Rhode Island’s March presidential primary may prove meaningful in the 2008 presidential election campaign, particularly if the Republican and Democratic contests remain unsettled after the string of contests on Feb. 5.

“Rhode Island may be very relevant here, and I’m not just saying that,” says Tad Devine, the Providence native and top Democratic consultant who is an expert on the presidential nominating process. “I think March 4 may be the day the Democratic nominee gets chosen.”

In modern times, Rhode Island has never figured in the primary system that decides the major party presidential nominees. The state’s primary was always held too late — by March the campaigns are usually effectively over.

But this time, events in both the Republican and Democratic campaigns have conspired to give Rhode Island a shot at importance, however fleeting.

On the Republican side, Arizona Sen. John McCain, former Arkansas Gov. Mike Huckabee, former Massachusetts Gov. Mitt Romney, former Tennessee Sen. Fred Thompson, and Rudy Giuliani, the former New York city mayor, are all vying for the nomination in a race that has become scrambled since the Iowa caucuses (won by Huckabee) and the New Hampshire primary (won by McCain.) Romney’s victory yesterday in Michigan has further roiled the Republican field.

The Democratic contest has narrowed to what most observers view as a two-candidate race between Illinois Sen. Barack Obama and New York Sen. Hillary Clinton, with John Edwards, the former North Carolina senator, hoping for a victory in an upcoming primary or caucus that might give his quest a lift.

Devine says that with both Obama and Clinton well-financed and garnering support from different wings of the party, the race could go on after Feb. 5. “Neither one of them is likely to get out if they keep winning delegates,” says Devine, who has worked as a top strategist on many Democratic presidential campaigns, including John Kerry’s in 2004 and Al Gore’s in 2000.

“I still really think this thing will be close to being wrapped up by 11 p.m. on Feb. 5, but you never know, and for Rhode Island’s sake, I hope it goes on to March 4,” says William Lynch, the state Democratic chairman and a Clinton supporter.

In past elections, Rhode Island’s orphan presidential primary has drawn scant attention; candidates rarely visited or spent much money on organization and advertising here. The event was known for having among the nation’s lowest turnout of any presidential primary.

One of the reasons it has traditionally been inconsequential is that no state or local decisions are made that day; voters participate only in the selection of delegates to the GOP and Democratic national conventions, where the presidential nominations are made.

Whether Rhode Island attracts candidates and attention probably depends on what happens on Feb. 5, which is the biggest day of the 2008 presidential nomination cycle. Democrats will hold elections in 22 states and one territory, with 1,681 delegates at stake. Republicans have 21 contests that day, with 975 delegates up for grabs.

On March 4, there are contests is Ohio, Texas, Vermont and Rhode Island. All of the other states — except Vermont — are bigger delegate prizes than Rhode Island, which has 32 Democratic delegates to the Democratic National Convention and 20 to the Republican National Convention.

By contrast, Texas has 228 Democratic delegates at stake and 140 Republican, Ohio’s Democrats have 116 delegates and the GOP 88. Vermont has 23 Democratic delegates and 17 Republican delegates.

The Republican race has become so scrambled that no one really knows what the field will look like in three weeks. In Rhode Island, there is spirited competition among GOP leaders for candidates Giuliani, McCain and Romney.

For example, Governor Carcieri is backing Romney and campaigned for his losing effort in the New Hampshire primary. Others who have signed up as Romney delegates include Kernan “Kerry” King, Carcieri’s legal counsel, and Rep. Joseph Trillo, R-Warwick.

McCain won the 2000 Rhode Island GOP presidential primary, defeating then-Texas Gov. George W. Bush in a record turnout. McCain campaigned here and was rewarded with a resounding victory. Rep. Robert Watson, R-East Greenwich, the House minority leader and a McCain confidant, says he hopes McCain comes back to campaign in the state before the March 4 vote.

“I’m really going to try to get him here,” said Watson. “There is a lot of regard for him here and of course he won in 2000.”

Other McCain supporters who have signed up for delegate slots include Rep. Susan Story, R-Barrington, David Dumas of East Greenwich, the former House Republican leader and current parliamentarian, Rep. Nicholas Gorham, R-Coventry, and his father, Bradford Gorman, a former House minority leader and state senator.

Giuliani has some institutional GOP support in the state. Among his backers are Warwick Mayor Scott Avedisian, Bernard Jackvony, the former lieutenant governor, Patricia Morgan, the former GOP state chairwoman, and Rep. Steven Coaty, R-Newport.

Huckabee’s delegates include a number of people who are not GOP activists and longtime party members, including Scott Bill Hirst and Robert Tingle, who has run unsuccessfully against Democratic Sen. Jack Reed.

Among Democrats, most of the party’s top elected leaders support Clinton, who has made many trips to Rhode Island to campaign for local Democrats. Her husband, former President Bill Clinton, is close to several state Democrats, including Mark Weiner, a veritable fundraising machine for the Clintons, and former Providence Mayor Joseph Paolino Jr.

All of the statewide elected Democrats and members of the state’s Washington delegation, except Reed and Rep. Patrick Kennedy, have signed on to Clinton’s effort. Reed is neutral and Kennedy supported Connecticut Sen. Chris Dodd, until Dodd’s recent departure from the race.

Obama draws support from some of the Democratic Party’s younger wing, including Rep. Joseph Almeida, D-Providence, Rep. Doug Gablinske, D-Bristol, and Edward Pacheco, D-Burrillville. Former Lt. Gov. Charles Fogarty, who narrowly lost the governorship in 2006 to Carcieri, has signed up as an Obama delegate, as has former Attorney General James E. O’Neil.

smackay@projo.com