Some takeaways from Tuesday's primaries in Mississippi and Alabama:
GINGRICH LOSES BIG
Newt Gingrich's campaign had said he had to win in the Deep South, and the former House speaker essentially staked his candidacy on strong victories in Alabama and Mississippi. But he failed to prevail, and his double loss raises questions about the future of his candidacy.
He, nevertheless, is vowing to press on. But that is all but certain to become more difficult given that he's only won two primaries so far _ in South Carolina on Jan. 21 and in the state he represented for 20 years in the House, Georgia, last week.
Plus, he's now facing calls for him to drop out.
Conservative rival Rick Santorum didn't name Gingrich but the message was clear when he called on conservatives to rally behind him _ and no one else.
PRO-ROMNEY SUPER PAC DIDN'T MAKE A DENT
Mitt Romney has benefited for months from the help of a pro-Romney super political action committee that pummeled his rivals with millions of dollars of negative TV ads. Every time a rival rose, Restore Our Future would beat him down _ and give Romney a chance to soar.
But the group's efforts in the Deep South didn't seem to have an impact. The super PAC poured more than $2 million into ads in Alabama and Mississippi, eclipsing what other GOP-leaning groups spent on the airwaves by roughly 4-to-1 in those states. The ads criticized Santorum for having voted in Congress to provide federal funding for Planned Parenthood and attacked Gingrich for supporting action with House Minority Leader Nancy Pelosi to combat climate change.
But Santorum won in both states as conservatives _ long skeptical of Romney _ flocked to the former Pennsylvania senator. On this night at least, a money advantage didn't seem to count for much.
ROMNEY STRUGGLES IN THE SOUTH
The former Massachusetts governor who ran the state as a moderate is the clear frontrunner in the race, and is on track to clinch the nomination if he continues amassing delegates at his current pace.
But he has yet to prove he can convince the base of his party to coalesce behind his nomination. Conservatives _ and evangelicals who rule in the Bible Belt _ have long viewed him skeptically because of his reversals and equivocations on issues they hold dear, like abortion, and his Mormon faith.
Tuesday's primaries in Mississippi and Alabama were the latest evidence of his trouble with the GOP base; Romney has failed to win in the party's only remaining regional stronghold.
Just a week ago, he was shellacked in Tennessee, Oklahoma and Georgia, and in January, he lost South Carolina.
Romney did manage to win Florida, but the state is so diverse that it isn't considered truly southern.
Look no further than the Deep South to see just how much power religious voters hold in the Republican Party.
In both Alabama and Mississippi, 80 percent or more of voters said they were born-again or evangelical Christians _ and more than seven in 10 said it mattered to some degree that a candidate shared their beliefs.
That gave Santorum an unmistakable advantage.
Exit polls showed that Santorum held an edge among those evangelicals, who said having shared beliefs "mattered a great deal" to their choices. Mississippi's evangelicals, for instance, were less keen on Romney; only about 27 percent saying they supported him, compared with 36 percent who supported Santorum.
THE GOP IS DEEPLY DIVIDED
Call it the contest between the right and the rest of the GOP.
That's the state of the protracted Republican nomination fight, as conservatives continue to split their votes between Santorum and Gingrich _ and resist a Romney candidacy.
It's at least partly a reflection of soul-searching that's been going on in the party for the past few years as Republicans quarrel over whether to back candidates who are pure on their issues or candidates who are more pragmatic.
Tuesday's double victories by Santorum illustrate the large degree to which the most conservative members of the GOP put their ideology first. He's considered more conservative than Romney, who argues that he's the more electable of the two.
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