Updated Mar. 18, 6:56 p.m. — Mitt Romney added to his advantage over his GOP rivals in the delegate tally by winning the Puerto Rico presidential primary on Sunday.
NBC News declared Romney the projected winner on Sunday evening. By virtue of the margin of his victory, Romney appeared on track to capture most — if not all — of the U.S. territory's 20 delegates by virtue of winning over 50 percent of the popular vote. (Any candidate who wins at least half of the popular vote wins all of Puerto Rico's delegates.)
The Puerto Rico primary, alongside caucuses held this weekend in Missouri, marked another step in the extended primary campaign, which has principally narrowed to a battle between Romney and former Pennsylvania Sen. Rick Santorum.
Reflecting the ferocity of their battle to amass the 1,144 delegates needed to secure the nomination, both Romney and Santorum traveled to Puerto Rico during the latter half of last week.
Romney said on Saturday during his visit that he was "cautiously optimistic" he would win the primary in Puerto Rico, where he enjoys the support of Gov. Luis Fortuño and his political organization.
"I care about you. I care about the people of Puerto Rico," Romney said. "Politics in puerto rico is spoken with energy and passion."
Both candidates spoke to a major issue in the territory — the prospect of making it the 51st state in the U.S. — during their visit. Romney has said he would support statehood if a majority of Puerto Rico voters support it. Santorum landed in a small political firestorm, though, by suggesting that Puerto Ricans adopt English as their lone official language as a condition for statehood.
Santorum backtracked, and blamed the media, whom he accused of taking his comments out of context.
“For someone to misrepresent and completely fabricate something that I never said or even intimated is very disappointing,” he said. “Hopefully that can set the record straight here and let people know that rick Santorum has been and will continue to be a friend of Puerto Rico."
The primary caps a weekend which also featured a caucus on Saturday in Missouri, which was different from the primary the state had held in February. Santorum won that primary – along with caucuses in Minnesota and Colorado that day – in a sweep which helped rejuvenate his campaign. But that Missouri vote was essentially meaningless; Romney did not campaign there, and the outcome had no bearing on the delegate count.
On Saturday, Missouri Republicans will caucus on the county level to elect delegates. Those delegates, in turn, will elect and bind national delegates to the candidates at congressional delegate caucuses on April 21 and at the state convention on June 2.
Because there is no formal straw poll accompanying this weekend’s caucuses, NBC News will not declare any formal “winner” in the contest.
Romney, the former Massachusetts governor who fell short of his goal of knocking out his GOP foes with a string of early caucus and primary victories, has the advantage over his GOP foes. He had won 423 delegates through last week, according to the NBC News delegate count; Santorum has won 184, Newt Gingrich 137, and 34 for Texas Rep. Ron Paul.
The contests serve as a precursor to the larger primary on Tuesday in Illinois, where Romney, Santorum and Gingrich have all fought for delegates alongside a victory in the statewide popular vote.
Romney was in Illinois on Sunday following his return from Puerto Rico. Santorum was there earlier in the weekend,