By Ros Krasny
(Reuters) - Mitt Romney, who regained front-runner status in the Republican presidential race with three state wins this week, could build on that momentum with a victory in the Washington state caucuses on Saturday just three days before crucial Super Tuesday voting.
The former Massachusetts governor led a Public Policy Polling opinion poll in Washington state on Friday, boosted by wins this week over main rival, former Pennsylvania Senator Rick Santorum, in Michigan, Arizona and Wyoming nominating contests.
"Romney has the momentum in Washington right now just as he does nationally," said Dean Debnam, president of PPP.
The poll showed Romney with 37 percent support, versus Santorum's 32 percent. Ron Paul had 16 percent and former U.S. House of Representatives Speaker Newt Gingrich had 13 percent Republicans are seeking a nominee to challenge President Barack Obama in the November 6 election.
The PPP poll surveyed 447 likely caucus-goers on Wednesday and Thursday and had a margin of error of 4.6 points. It was a marked turnaround from a mid-February survey that had Romney trailing by 11 points, shortly after Santorum pulled off upsets in Minnesota, Missouri and Colorado nominating contests.
But the latest survey also revealed a possible weakness for Romney: Santorum might be a greater threat to him if caucus turnout is low.
Caucuses, as opposed to primaries, are lengthy affairs that voters who are less than fully committed shy away from because of the time needed to participate. That could hurt Romney.
"The big question in a low turnout caucus is whether his supporters are passionate enough to show up. If Santorum's supporters care more, they could still put him over the top," Debnam said.
Romney had only a 3-point edge among those who said they would definitely turn out for the caucuses, where voters need to take some two hours electing delegates to the state convention and doing other official party business as well as choosing a presidential favorite.
"Romney's support is about a mile wide and an inch deep," said Gary Bullert, a political science professor at Columbia Basin College in Pasco.
Romney is likely to do well with moderate Republicans in the urban, densely populated northwest "Starbucks Belt" of Seattle, Tacoma, and the state capital, Olympia.
In the southwest and especially in rural eastern Washington, many Republicans support socially conservative Santorum, and Paul, a libertarian Texas congressman.
The presidential vote is a non-binding straw poll, and state delegates will be chosen later, in order to avoid allocating delegates to candidates who later drop out. The West Coast state has not voted for a Republican in a presidential election since 1984.
SUPER TUESDAY COMING UP
"How often has the state of Washington had the ability to reset a presidential race?" Santorum said in a speech on Thursday at a church in Spokane, the hub of eastern Washington. "I know you feel like you've been railroaded and bulldozed. Well, now you have a chance to speak to the country."
For the first time in recent memory, the state's vote comes before Super Tuesday contests in 10 states next week, making it an indicator of momentum for the candidates rather than an afterthought. All four remaining Republican hopefuls have visited the state recently.
"There is an extremely high level of enthusiasm for the caucuses and there has been unprecedented press coverage," said Kirby Wilbur, state Republican Party chairman, who predicted record turnout.
"This is the first time we've had any candidate come to the state, let alone four, and it's really pumped up the base," he said. "Winning here will be a psychological boost for the winner going into Super Tuesday."
Also boosting turnout: Unlike in past years ,Washington is not holding a primary election in addition to the caucus, saving the cash-strapped state government about $10 million. Voters have been told the caucus is the only chance to have their say.
Wilbur predicted that based on the strength of respective ground organizations, Romney's biggest competition on Saturday would come from Paul, not Santorum.
"Paul's people have been here for six months. They've been organizing strongly," said Wilbur. Romney has also ramped up a significant get-out-the-vote operation in the past month.
Paul has yet to win a state nominating contest but his strength has been in caucuses and in turning out his enthusiastic supporters. He drew large crowds in the state February and held three events on Friday.
"It's all about who shows up to vote, and that plays in favor of Ron Paul," said Bullert, who said the Texan continued to tap into dissatisfaction with both major political parties. At least some Democrats are expected to vote on Saturday in the open caucus.
As in other states, Romney has the support of most of the party establishment, including endorsements from three of the state's four Republican members of Congress and a number of statewide office holders.
Nationally, he has a clear lead in the delegate count, although he is far from gaining the 1,144 delegates needed to secure his party's nomination for November's election.
(Additional reporting by Sam Youngman; Editing by Peter Cooney)