WASHINGTON (AP) -- Rick Santorum was turning in his most impressive performance yet with conservatives and blue-collar voters as he rode to triumph Saturday in Louisiana's Republican presidential primary, capturing robust support from nearly all types of people, according to preliminary results of an exit poll.
Highlighting his strength, the former Pennsylvania senator bested Mitt Romney for the first time among those calling the economy the campaign's dominant issue. As usual so far this year, more voters named the economy as their top concern than any other problem and more than 4 in 10 of them said Santorum was their candidate -- an embarrassment for Romney, the former venture capitalist who has claimed he knows best how to create jobs.
Romney retained his usual advantage among voters whose most prized characteristic in a GOP candidate is finding someone who can defeat President Barack Obama this fall. But illustrating the narrowness of the former Massachusetts governor's appeal in the state, more than half of Romney's Louisiana voters were from families earning at least $100,000 a year, the first time that has happened this year with any GOP presidential hopeful.
Overall, the results painted Louisiana as a state whose Republicans are tailor-made for Santorum, with large numbers of conservative and religiously motivated voters.
Santorum was winning the votes of half of both conservatives and tea party supporters, his high water marks with both groups so far in 2012. He was doing slightly better than that among those without college degrees -- a measure of blue-collar voters.
The devoutly and openly religious Santorum was also getting almost 6 in 10 votes from white born-again and evangelical voters and from those saying it is important that they share religious beliefs with their candidate -- his best showings of the year with two groups that have become one of his strengths.
In another area where he was doing slightly better than he had previously, more than 4 in 10 Saturday cited Santorum as the candidate who best understands the typical American, about doubling the number citing Romney for that quality.
Only around 1 in 5 Louisiana voters said they were influenced by a Romney aide's comment likening his campaign's tactics to an Etch A Sketch toy, one of last week's top political stories.
Those who said Eric Fehrnstrom's remark played an important role in their choice were leaning toward Santorum over Romney by about a 3-1 margin. But Santorum was also leading by double digits among those saying the comment was not significant for them.
Asked whether Romney's positions in the GOP primary might make him too conservative for more moderate voters in November's general election, Fehrnstrom had said the campaign could start over in the fall, saying, "It's almost like an Etch A Sketch. You can kind of shake it up."
Romney's opponents said the remark shows he shifts his views too easily.
The few groups where Romney was leading included people earning over $200,000 a year and people expressing little concern about sharing religious beliefs with their presidential favorite.
Almost 2 in 3 Louisiana voters said they strongly support their candidate, one of the strongest measures of intensity in any state so far. Majorities also said they would be content if Romney, Santorum or former House Speaker Newt Gingrich ultimately won the nomination.
Even as some national Republican leaders have started calling for Romney's rivals to drop out and begin uniting the party for the fall campaign, only about 1 in 4 Louisiana voters said they want the GOP contest to end quickly, even if their contender loses. Seven in 10 said they were happy for the party's internal battle to continue as long as their candidate wins.
Just over half of Louisiana voters said the economy is the issue they most care about, a bit more than the number of voters have typically said in other states.
The survey was conducted for The Associated Press and the television networks by Edison Research as voters left their polling places at 30 randomly selected sites in Louisiana. The survey involved interviews with 1,499 voters and has a margin of sampling error of plus or minus 4 percentage points.