By THOMAS BEAUMONT
DES MOINES, Iowa (AP) - Republican-leaning areas in states vital to President Barack Obama's re-election prospects are drawing top-tier Democratic congressional candidates who, even if they lose, could help turn out the vote and boost Obama's chances of winning a second term.
The best example of the trend is former Iowa first lady Christie Vilsack, challenging GOP Rep. Steve King in Iowa's 4th Congressional District.
Christie Vilsack, the wife of former two-term governor Tom Vilsack _ now Obama's agriculture secretary _ moved more than 100 miles away from her home to run in a largely rural tract of GOP-heavy northern and western Iowa, where Obama lost in 2008 despite winning the state.
Other key matchups are in Colorado, Florida, Ohio and Virginia. Obama carried those four states four years ago while losing to Republican John McCain in the individual counties that make up the districts.
The president is counting on heavy turnout in strong Democratic districts. He also hopes to improve the odds of beating Mitt Romney by cutting into the likely Republican nominee's edge in GOP districts in key states by not allowing the incumbents to coast to re-election.
These five states with such House races are important to Obama because he won them four years after Republican George W. Bush's narrow re-election as president in 2004. Along with Nevada, which has no similar House race this year, they form the core of the battleground that Obama is defending and that Romney hopes to cut into in the race for 270 electoral votes needed to win the Nov. 6 presidential election.
Bush narrowly carried Iowa in 2004 by running up big margins in the counties King represents. The outspoken conservative faced nominal competition for re-election that year. He spent his campaign money in the final weeks on radio ads touting his opposition to gay marriage in an effort to drive social conservatives to the polls, which helped push Bush over the top.
Obama aides declined to comment on campaign strategy.
Democrats, with 190 members in the Republican-controlled House, think they can net the 25 seats needed to retake the majority the party lost two years ago. House Speaker John Boehner of Ohio described his challenge this way: "What I'm trying to do is to wake some people up and realize that we've got a challenge here, and we've got 242 Republicans, incumbents, all up for election, 53 of them in pretty tough races."
Democrats count Vilsack and the others in battleground states as more than token challengers, even if they still face uphill races.
_ In Florida, Orlando Police Chief Val Demings is challenging first-term Republican Rep. Daniel Webster in the 8th District, a GOP-leaning one that surrounds Democratic-leaning Orlando in central Florida. McCain carried the district with 52 percent in 2008. Bush carried it in 2004 with nearly 58 percent.
_ In Colorado, state Senate President Brandon Shaffer is challenging freshman Rep. Cory Gardner in the 4th District, which includes most of the state's conservative eastern plains. McCain carried the district with 56 percent of the vote. Bush won it with 64 percent.
_ Ohio's 6th District features a Democratic comeback effort by former Rep. Charlie Wilson against freshman GOP Rep. Bill Johnson. McCain and Bush won the coal-heavy, blue-collar district along the Ohio River with about 53 percent.
_ In Virginia's 5th District, John Douglass, a retired Air Force brigadier general, is the Democratic favorite to challenge freshman Republican Robert Hurt. McCain carried the southern Virginia district with 53 percent. Bush won it with 57 percent. Virginia's House primary is June 12.
Former Kerry aide Steve Elmendorf said Obama's team has a deep understanding of how congressional races can help him.
"It's to President Obama's benefit to have strong people on the ballot below him," said Elmendorf, Kerry's 2004 deputy campaign manager.
Longtime Republican strategist Charlie Black said the Vilsack-King race could be a factor for Obama, but that the presidential race usually drives turnout.
"There could be isolated examples, like the Steve King example, where a congressional race drives turnout, and the top of the ticket benefits. But there wouldn't be many," said Black, who has advised GOP candidates for more than 30 years.
King is seeking a sixth term in a district slightly less favorable than the one he has represented for almost 10 years, a change that followed the redrawing of congressional district lines after the 2010 census.
Republicans in King's new 4th District still hold a 46,000-voter registration edge over Democrats. McCain won the counties that make up the new district with 54 percent of the vote, while Bush got 55 percent.