A diverse mix of voters in Ohio helped shape today's headline Super Tuesday contest, with results that highlighted tensions evident in the Republican race all year: Mitt Romney leaning on his standing as the most electable candidate, Rick Santorum honing his appeal to conservatives and more religious voters, and leading Romney as the candidate of the common man and woman.

In other states, where the electorate was more homogenous - either much more conservative, as in Oklahoma, or much less so, as in Massachusetts and Vermont - the story was a different one. Ohio's demographic and attitudinal diversity earned its battleground reputation.

As elsewhere, electability worked best for Romney. Fifty-one percent of Ohio voters saw him as the candidate best able to defeat Barack Obama in November - and seven in 10 of them voted for him. In another measure, 42 percent called electability the single most important candidate attribute in their vote - and Romney won more than half of their number, vs. just 27 percent for Santorum.

However, a combined total of 38 percent in Ohio instead said they were looking chiefly for someone with strong moral character, or for a true conservative - and in these groups combined, 55 percent voted for Santorum, just 16 percent for Romney.  And notably, Santorum beat Romney as the candidate who "best understands the problems of average Americans," 33-22 percent. Nearly as many picked Newt Gingrich and Ron Paul, 18 and 17 percent, respectively, as selected Romney on empathy.

Another potentially key split was by gender: Exit poll results found an exact even split between Santorum and Romney among men. By contrast, Romney held an 11-point lead over Santorum among working women in Ohio, and led by 14 points among non-married women - perhaps marking Santorum's controversial comments on some women's issues.

Politically, nearly seven in 10 voters in Ohio were Republicans, down from their share in the state's primary in 2008 but more than last week's Michigan primary; a quarter were independents. While Romney generally has done better with mainline Republicans than with non-Republicans this year, the margin in Ohio's exit poll was very close.

Slightly fewer than half of Ohio voters were evangelicals - far fewer than in the Southern states voting Tuesday. Santorum led in this group by 16 points. Santorum held a much larger 31-point lead among voters who said it matters "a great deal" that they support a candidate who shares their religious beliefs. And among very conservative voters, another key group in which Romney's struggled this year, Santorum had 48 percent support, compared to Romney's 31 percent.

Economic status also again was a factor. Romney did best by far among better-off voters, winning, for example, those with $100,000-plus incomes by 16 points (and those with $200,000-plus incomes by 29 points). It was much closer in less well-off groups. And Romney won college graduates, but not those who lack a college degree.