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Romney viewed as most electable but not enough to help him break through big in Dixie

In a speech to his supporters, Republican presidential contender Rick Santorum said, "we're on our way to victory in this election" after winning primaries in Mississippi and Alabama.

Updated at 10:50 p.m. ET:  Exit poll interviews with Republican voters in Tuesday’s Alabama and Mississippi primaries found that Mitt Romney’s positions on the issues weren’t conservative enough for most voters in both states.

NBC News declared Rick Santorum as the projected winner of both the Alabama and Mississippi primaries. Romney was running third in both states, behind Newt Gingrich.

Yet a plurality of Tuesday’s voters also picked Romney as the candidate most likely to defeat President Obama in November.

By large majorities in both states, voters said the economy – not abortion, illegal immigration, or the federal deficit -- was the issue that mattered most in deciding how they voted – and Romney did better among such voters than his rivals Santorum and Gingrich, but not enough to score a victory in Alabama or Mississippi.  (Rep. Ron Paul was a minimal factor in both states.)

Santorum continued to enjoy strong support from social conservative voters -- but he also continued to lose many of those voters to Gingrich.

Take for example, anti-abortion voters, who accounted for about seven out of every ten voters in each state. The antiabortion voters in Alabama preferred Santorum: he won 42 percent of them, to Romney’s 21 percent and Gingrich’s 30 percent. In Mississippi 36 percent of the antiabortion voters chose Santorum, while 31 percent chose Romney and 28 percent went for Gingrich.

Exit poll data from South Carolina, Georgia and Tennessee showed that Romney, a Mormon, was only to draw between a fifth and a quarter of the evangelical Christian voters in those contests. But among white evangelical Christians in Mississippi Romney did better, winning 31 percent, while Santourm won 35 percent. In Alabama, evangelical Christians preferred Santorum: he won 35 percent of them, with Romney picking up 27 percent and Gingrich 32 percent.

How much did it matter to voters on Tuesday that a candidate shared or didn’t share their religious beliefs? In both states, about three out of four voters said shared religious beliefs mattered a great deal or somewhat. The exit poll found contrasts in views: in Alabama, 40 percent of such voters chose Santorum, while in Mississippi a plurality of those voters – 34 percent – chose him and 32 percent supported Romney.

Even in these two socially conservative states, there were some Republican voters who were willing to identify themselves to exit poll interviewers as “moderates,” or say they thought abortion should be legal. Among self-identified moderates – who were nearly one out of four voters in Alabama -- Romney was the winner with 41 percent. In Mississippi, where moderates were about two out of ten voters, Romney won the moderate vote with 46 percent.

In each state, roughly one in four voters said abortion should be legal: Romney won 36 percent of them in Alabama and 39 percent of them in Mississippi.

Putting social issues aside, Romney showed strength among voters in both states who picked the economy as the most important issue, Romney was the leader with 35 percent.

Romney was by far the strongest candidate among voters who might be called pragmatists: those who said defeating Obama is the candidate quality that mattered more than moral character, prior experience in business or government, or ideological conservatism.

Although Romney has had trouble appealing to lower-income voters in other primary states, in Mississippi he won nearly the same percentage of voters with annual family incomes of under $50,000 – 30 percent -- and of those with annual incomes over $50,000, 33 percent.

In Alabama there was a bit more of a gap: Romney won 26 percent of voters with incomes under $50,000 and 31 percent of voters with incomes over $50,000.

The twice-divorced Gingrich suffered from a significant gender gap: he won 27 percent of women voters in Mississippi, but won 32 percent of male voters; while in Alabama he ran 11 points worse among women (24 percent) than among men (35 percent).

In contrast, Romney ran better among women in Mississippi (getting 34 percent of their votes) than among men (getting 31 percent of male voters). Romney ran about even among male and female voters in Alabama but Santorum ran better among Alabama women (37 percent) than among men (30 percent).