LEESBURG, Va. — The outcome of the presidential race probably will depend on what occurs in the 106 counties that Republican George W. Bush won in 2004 and that President Obama won in 2008, according to an Associated Press analysis.
Those counties are full of fickle voters inclined to swing between Republican and Democratic candidates every four years. All are targeted as the president and his Republican challenger look for enough victories in enough states to reach the 270 electoral votes needed to capture the White House.
The race may come down to an even narrower slice of the electorate than the nine most contested states: Colorado, Florida, Iowa, Nevada, New Hampshire, North Carolina, Ohio, Virginia, and Wisconsin.
The AP reviewed vote returns in those nine states during the 2000, 2004, and 2008 elections to identify the counties that have swung between the parties and were most likely to do so again Nov. 6.
In these counties more than anywhere else, voters’ phones ring each night with automated telephone surveys. Every day, glossy mailers hit their mailboxes. TVs crackle day and night with campaign ads.
In fact, voters in the Cincinnati, Tampa, and northern Virginia TV markets have been subjected to presidential campaign advertising totaling $127 million, almost one-fifth the total spent nationwide this year.
‘‘There’s more — and more concentrated — contact with voters in these counties that swung back and forth in these states than anybody,’’ said Charlie Black, a veteran Republican presidential campaign strategist and informal Romney adviser.
In a race where any bit of an advantage could make the difference, the campaigns go to all this trouble to sway a tiny fraction of the electorate. In 2008, there were 6.2 million votes from those 106 counties; that was not even 5 percent of the roughly 137 million who voted for president.
There is no single reason to explain why these counties seem to shift with the political wind. Their voters are far from monolithic, having little in common other than their voting patterns.
In most of these places, there are few undecided voters, forcing Obama and Romney to subdivide the electorate in an attempt for any edge.
In northern Virginia, for example, Obama is reaching out to newcomers and younger veterans. Romney’s pitch is stronger toward retired military members, sportsmen, and social conservatives.
In counties in the West, Obama is courting educated women and Hispanics. Romney is trying to make inroads with both but is more focused on businesswomen and small-business owners.
As a whole, voters in these counties are less racially diverse than the nation, with a smaller percentage having a college education.
One such area is working-class Sandusky County, Ohio, where the automotive industry rebound has pushed the county’s unemployment below the state average.
If there’s one area where these counties are linked, it may be that many have a wide segment of working-class white voters, an important group for Romney and one that Obama has struggled with.
In the hunt for 270, Obama starts with more states and electoral votes in his column. Romney must take back from the incumbent some states that Obama carried four years ago, including North Carolina and Virginia, which had been reliably Republican until 2008.
Newspapers in battleground states making their endorsement choices
President Obama and Republican challenger Mitt Romney secured newspaper endorsements Sunday, each picking up support in swing states.
In Ohio, the nation’s most hotly contested battleground, Obama was endorsed by the Cleveland Plain Dealer and the Akron Beacon Journal, while Romney got the backing of the Columbus Dispatch.
“Ohio in particular has benefited from his bold decision to revive the domestic auto industry,” the Plain Dealer’s editorial board wrote about Obama. “Because of his determination to fulfill a decades-old dream of Democrats, 30 million more Americans will soon have health insurance.
“His Race to the Top initiative seeded many of the education reforms embodied in Cleveland’s Transformation Plan. He ended the war in Iraq and refocused the battle to disrupt Al Qaeda and its terrorist allies. He ordered the risky attack inside Pakistan that killed Osama bin Laden.”
The Dispatch wrote that “in 2008, Americans made a leap of faith when they elevated the inexperienced Obama to the White House. That faith was not rewarded. This time, voters should place their hopes for change in experience, by electing Romney.”
Papers in other swing states focused on the economy in their endorsements of Romney.
New Hampshire’s Union Leader wrote that “Romney offers a better way, a realistic way, to restore American prosperity.”
“Seasoned executive Romney would come to office ready to put the country on the course to more freedom and prosperity,” the Tampa Tribune said.
In North Carolina, the Asheville Citizen-Times concluded that Romney’s positions have been too inconsistent during his political career.
“With Obama, we know what we are getting,” the Citizen-Times wrote. “He has consistently embraced the concept of community. Obama believes we are not just a bunch of individuals but a nation, and that we must work together to address the challenges we face.”
Other newspapers endorsing Obama included the Los Angeles Times, Arizona Daily Star, and Santa Fe New Mexican.
Romney was endorsed by the Pittsburgh Tribune-Review, Arizona Republic, and Fort Worth Star-Telegram.