WASHINGTON (AP) — Republican Mitt Romney is faltering with white working-class voters crucial to his party's drive to capture the White House, even as he tries to fend off a rising GOP challenger, Rick Santorum, who wields strong blue-collar appeal.The wealthy former Bain Capital chief has led his rivals by comfortable margins among white college graduates, according to combined polls of voters in the first five states that held presidential nominating contests. But the exit and entry surveys showed only a modest Romney advantage among whites who lack college degrees, the yardstick analysts typically use to define the working class.The imbalance was most pronounced among less-educated white men, with whom his lead disappeared.More recent polling bears out the same problem for Romney. According to a national poll of Republicans released this week by the nonpartisan Pew Research Center, the former Massachusetts governor has a slender lead over Santorum among whites with degrees but trails him among working-class whites, 36 percent to 23 percent.Romney's lukewarm performance with less-educated whites could haunt him in the Feb. 28 Michigan primary. Though it's Romney's native state, Santorum is using his upbringing in the western Pennsylvania manufacturing town of Butler, his rougher-edged style and his "Made in America" proposals for boosting U.S. manufacturing to woo Michigan's many blue-collar voters.Romney's weakness with working-class whites is a liability he would also have to address as the nominee. GOP presidential candidates often need big margins from this group to offset weaker support from others."It has to be a concern," said GOP pollster John McLaughlin, who is not working for a presidential candidate. "What these voters are looking for is, 'Tell me how you're going to help my life.' If we can't articulate that, then we're going to lose."Some voters view Romney as "an ultra-wealthy individual," said David Hill, another GOP pollster who is not working in the presidential race. "They have a sense he cannot identify with ordinary Americans. He'll have ample time over the course of campaigning in the general election to rectify that."The sometimes-staid Romney is already trying to do just that.He recently described his father as a carpenter who could spit nails out of his mouth "pointy end forward," without mentioning that George Romney became CEO of the American Motors Corp. and governor of Michigan. He also described how rising fuel and food prices have been "tough for middle-income families in America," and said the country needs a president with "experience in a factory or experience in a workplace" who can understand how to create jobs.Santorum, son and grandson of Italian immigrants, has a more personal connection to working-class voters that he's always ready to discuss. He cites his childhood living in apartments provided by the Veterans Administration, where his father worked as a psychologist, and never misses an opportunity to discuss his grandfather."My grandfather was a coal miner. I grew up in a steel town, with blue-collar roots," the now well-off former Pennsylvania senator said Tuesday in Boise, Idaho.Strategists and political scientists attribute Romney's problem partly to his personal wealth and financier background and a string of statements his opponents have used to characterize him as an out-of-touch patrician. He has jokingly called himself unemployed, said he knows what it is like to fear a pink slip and characterized his $373,000 earnings from paid speeches as "not very much" money.Romney has also been hurt by his tax returns. They show he pays around 15 percent of his income in taxes — less than many middle-income families — and has placed some assets in Swiss bank accounts and other exotic locations like the Cayman Islands."There's no identification, no connection that he makes with some of these voters," said Terry Madonna, a political scientist and pollster at Franklin & Marshall College.Romney pollster Neil Newhouse says his candidate's early showing with the working class has been "a soft spot" because Santorum and Gingrich have targeted those same voters. That won't translate to Election Day, Newhouse said."The general election will be about President Obama and his accomplishments and lack thereof," Newhouse said.Combined figures for the first five states to vote — Iowa, New Hampshire, South Carolina, Florida and Nevada — show ideology was also a factor. Just 22 percent of Romney's votes came from working-class whites who consider themselves very conservative. Santorum got 52 percent of his votes from that group and former House Speaker Newt Gingrich, Romney's biggest rival at the time, got 45 percent.In those early contests, Romney led Gingrich by 43 percent to 28 percent among whites who completed college, the polls show.That gap shrank to a 39 percent-to-33 percent Romney advantage among whites without college degrees. White men who haven't graduated college tilted 37 percent to 33 percent toward Gingrich.Romney's 20-percentage-point advantage over Gingrich among white female college graduates in those states falls slightly, to 15 points, among less educated white women.Santorum swept GOP presidential contests in Colorado, Minnesota and Missouri last week. There were no exit polls in those races, but the combined surveys for the first five states show Santorum, who had not yet built momentum as a candidate, trailing both Romney and Gingrich badly among white working-class voters.Ironically, Romney's problem echoes an even more serious weakness that candidate Barack Obama showed in 2008 when trying to reach those same working-class white voters.Obama lost them badly in the Democratic primaries to rival Hillary Rodham Clinton before losing them by 18 percentage points to GOP candidate Sen. John McCain that November. Obama remedied that by coming close among white college graduates and prevailing overwhelmingly among minorities.Republicans want to drive their margin among working-class whites as high as possible this year to offset Obama's advantage with minorities. Working-class whites comprise around 4 in 10 voters in recent general elections.Obama campaign spokesman Ben LeBolt says Romney will be hurt among these voters by his background at Bain, the private equity firm, whose corporate buyouts sometimes eliminated jobs."The essential question of the election is, 'Who's going to restore economic security for the middle class?'" LeBolt said.The data is based on surveys conducted for The Associated Press and the television networks by Edison Research as voters arrived at or left randomly selected sites in this year's GOP caucuses and primaries in Iowa, New Hampshire, South Carolina, Florida and Nevada. The results of the five surveys were combined and each was weighted to reflect its share of the votes cast.The combined survey involved interviews with 11,376 voters and had a margin of sampling error of plus or minus 1 percentage point.___AP Deputy Director of Polling Jennifer Agiesta and Associated Press writers Philip Elliott and Steve Peoples contributed to this report.