Rick Santorum has won the Mississippi GOP presidential primary, according to an Associated Press projection, following his earlier triumph in neighboring Alabama on Tuesday.
The dual victories are a major boost to the former Pennsylvania senator's campaign at a time when the primary calendar favors him. He's spending tonight in Louisiana, another deeply conservative state which holds a March 24 primary.
Speaking at his campaign headquarters there, Santorum rallied his supporters with what he portrayed as another against-the-odds turn in his underdog campaign.
"This campaign is about ordinary folks doing extraordinary things, sort of like America," Santorum said, just before Mississippi was called for him. As he spoke, one network declared him the winner there, and the crowd erupted.
The final results in both states appeared to be as close as advertised. Since both states divvy up their delegates proportionally, neither of the three leading candidates is likely to emerge with much of a delegate advantage.
But the twin losses could prove to be a significant blow to Newt Gingrich's campaign, which had been pursuing a "Southern strategy."
Gingrich had stayed out of most of the Super Tuesday states and the preceding primaries in Arizona and Michigan. His only victories now are from his home state of Georgia and neighboring South Carolina.
The former House speaker had also spent the most days campaigning in Mississippi this year -– four, according to one count from NBC News. Santorum had three days of campaigning there and Romney two. Ron Paul, who finished a distant fourth, never visited.
The Magnolia State GOP contest was the rare one in which all three leading contenders made a serious effort. And with Santorum and Gingrich dividing up the more conservative electorate, Mitt Romney's campaign seemed to sense in the closing days that they had a real, unexpected chance to win.
Romney had the endorsement of the state's new GOP governor, Phil Bryant. Former Mississippi Gov. Haley Barbour, a GOP power broker who himself considered running, chose not to endorse.
Santorum hopes the results will sideline Gingrich and give him the head-to-head with Romney he's long been hoping for.
"The time is now for conservatives to pull together. The time is now to make sure, to make sure that we have the best chance to win this election -- and the best chance to win this election is to nominate a conservative to go up against Barack Obama who can take him on on every issue."
Even as the Romney campaign has said it would take "an act of God" for Santorum to claim enough delegates to do so, he vowed: "We are going to win this nomination before that convention."
Exit polls showed that the ability to defeat President Obama was the top quality voters were looking for in a candidate, accounting for 42% of those who turned out. Nineteen percent said having a candidate who is a true conservative was the top concern.
Whoever wins the GOP nomination is certain to carry the state against President Obama in the general election. Mississippi has not gone for a Democratic candidate since Jimmy Carter carried the state in 1976.
Southern sweep: Rick Santorum takes Mississippi and Alabama