|Romney, despite wins, remains unpopular for moderate past positions on issues like abortion and gay rights [Reuters]
Republican presidential hopeful Mitt Romney has swept to victory in his party's primary in Puerto Rico, bolstering his position as front-runner in the race to determine who will face Democratic President Barack Obama in the November 6 election.
With 31 per cent of the ballots counted on Sunday, Romney had about 83 per cent of the vote, according to Puerto Rico's electoral commission. Rick Santorum was in second place with just over 8 per cent. Newt Gingrich was third with about 2 per cent.
With more than a majority of the vote, Romney looked likely to win all 20 of the delegates up for grabs.
"There are only 20 per cent of the votes in and yet CNN has called it for me," Romney told a rally in Vernon Hills, Illinois.
"Apparently the reason they were able to make the call was that, with only 20 percent in, 83 per cent of the people of Puerto Rico, those who voted, voted for me. So that's a pretty good start. So I intend to become our nominee and I intend to get Latino voters to vote Republican and take back the White House. We're going to get that job done," he said.
Romney has a big lead in support from party delegates, whose backing is needed to win the nomination. But he faces a growing challenge from Santorum in Illinois, which holds its primary contest on Tuesday (March 21), in the months-long fight to win the 1,144 delegates needed to seal the Republican nomination.
'Flawed' and unpopular
The former Massachusetts governor and multimillionaire, who accumulated his fortune buying and selling troubled business ventures, has proven singularly unable to win the hearts of the base of the Republican party - an increasingly conservative bloc of voters who distrust Romney for his moderate past positions on important social issues like abortion and gay rights.
As the day began, Santorum, a former Pennsylvania senator, claimed he was in the contest for the long haul because Romney is a weak front-runner even though he comfortably leads in the fight for delegates to the nominating convention.
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Santorum campaigned on Sunday in the southern state of Louisiana, which holds its primary on Saturday.
"This is a primary process where somebody had a huge advantage, huge money advantage, huge advantage of establishment support and he hasn't been able to close the deal and even come close to closing the deal," Santorum said of Romney. "That tells you that there's a real flaw there."
Romney is on pace to capture the nomination in June unless Santorum or Gingrich is able to win decisively in the coming contests.
Both Santorum and Romney campaigned last week in Puerto Rico, the US commonwealth island in the Caribbean island, where residents are US citizens but cannot vote in the November presidential election.
Romney secured the endorsement of Puerto Rico govenor Luis Fortuno and other leading politicians.
Santorum hurt himself with statements that English would have to be the official language if the US territory were to seek statehood.
Room to race
The former speaker of the House of Representatives has focused his campaign in the Deep South of the United States, but even at that he finished second to Santorum in Mississippi and Alabama.
Santorum wants Gingrich to leave the race, a move that would allow Santorum to consolidate the conservative opposition against Romney.
Both Santorum and Gingrich have said they would stay in the race and perhaps force the nomination to a fight at the Republican convention in Tampa, Florida, if Romney does not amass enough delegates to arrive with a mandate.
Santorum hopes that a strong showing in the remaining state contests would enable him to claim a mandate and persuade delegates to ignore election results in their states and go with him as the more conservative option over Romney.
But there is a hitch, and that is Gingrich's refusal to quit the race even though he has only won primaries in South Carolina and Georgia, which he represented in Congress for two decades.
Romney's aides call this a fantasy scenario even as they try to prevent delegates from defecting.
As Puerto Rico voted, Romney and Santorum traded barbs from afar on national TV news programmes and at campaign events.
"Sen. Santorum has the same economic lightweight background the president has," Romney told a crowd in Moline, Illinois.
That drew a Santorum retort: "If Mitt Romney's an economic heavyweight, we're in trouble."
Aside from a pair of TV interviews, Santorum spent the day visiting a pair of churches in Louisiana, sharing how his faith has shaped his political career and his opposition to abortion rights and gay marriage.
He did not mention Romney or any of his other Republican opponents during talks at both churches.
He made clear he did not plan to exit the race anytime soon, saying in Bossier City, Louisiana, "One of the great blessings I've had in every political campaign is people underestimate me, people underestimate what God can do."