Santorum leading in Alabama; Close three-way race in Mississippi
Updated: 9:50 p.m. ET (For an updated story, click here)
In Alabama, CBS News estimates Rick Santorum is leading both Romney and Gingrich.
Polls in both states closed at 8 p.m. ET.
Full Alabama results
Full Mississippi results
In Mississippi, with 71 percent of the votes in, Santorum had 33 percent support, while Gingrich had 32 percent and Romney had 30 percent.
In Alabama, with 26 percent of precincts counted, Santorum had 35 percent support, followed by Gingrich, with 30 percent. Romney followed with 28 percent support.
According to early exit polls out of Alabama, Santorum is leading among women, very conservative voters, and white evangelical voters. White evangelical voters make up about 80 of the Alabama electorate.
The same exit polls show Newt Gingrich leading among Alabama men.
Romney, however, is winning the votes of Republican voters in Alabama who pick the economy as their top issue, as well as those who say defeating President Obama is the most important quality in a Republican presidential candidate.
In both states, Romney is dogged by the notion that he is insufficiently conservative: More than half of Alabama primary voters and Mississippi voters alike say Romney's issue positions are not conservative enough. In Mississippi, 49 percent of voters say Santorum's positions on the issues are about right, while 56 percent say the same of Gingrich. In Alabama, more than 50 percent of voters say both Gingrich and Santorum's positions on the issues are "about right."
In Mississippi, Romney has the backing of women. He also wins on electability and the economy, and is viewed as the candidate with the best chance of beating Obama.
Alabama exit poll
Mississippi exit poll
Gingrich, on the other hand, has a small lead with men, and is seen as the candidate who best understands the problems of average Americans.
According to exit polls, 83 percent of primary voters in Mississippi identify as born-again or evangelical Christians.
Polling out of Alabama and Mississippi ahead of Tuesday's contest showed close contests between Romney, Santorum and Gingrich, although Romney at one point referred to the region as "a bit of an away game" for him. A victory in the conservative South would help Romney demonstrate he has the ability to rally his base. Any wins for Gingrich could help him demonstrate his strength in the region, while they would allow Santorum prove he is the authentic conservative and alternative to Romney.
Although he can't secure the nomination on Tuesday, Romney told reporters earlier in the day that he's hoping to walk away with "a third" of the delegates at stake in the contests.
"You don't know from polls what will happen but obviously if the polls are anywhere near correct, we'll end up with, I don't know, a third of the delegates," he said. "And if that's the case, why, that inches us closer to that magic number."
According to Bloomberg, Romney and super PACs backing him outspent his Republican rivals considerably on advertisements in Mississippi and Alabama.
In Mississippi, Romney may also be getting a boost from the endorsement of Gov. Phil Bryant, who earlier this week lent his support to the candidate and said he thinks Romney can win his state.
There are also caucuses going on tonight in Hawaii, although results are not expected until early Wednesday morning.
