WASHINGTON - Loretta Mitchell is 100 percent sure she's going to vote in the presidential race come November. She doesn't have a clue who'll get that vote.

That makes her a rare and highly sought after commodity: an undecided likely voter.

The challenge for President Barack Obama and Republican Mitt Romney is how to lay claim to this small but mightily important swath of the electorate. These people are truly up for grabs, claim they're intent on voting and yet aren't paying that much attention.

With six hard-fought weeks left in the campaign, just 7 percent of likely voters have yet to pick a candidate, according to an Associated Press-GfK poll. When combined with those who are leaning toward one candidate or the other but far from firm in their choice, about 17 percent of likely voters are what pollsters consider "persuadable."

That includes 6 percent who give soft support to Obama and 4 percent for Romney.

Mitchell, a 68-year-old independent from the small town of Lebanon, Ind., voted for Obama in 2008 but says both candidates this year strike her as "true politicians, and I'm just really down with Washington and politicians."

Like a lot of undecideds, she isn't sure what's going to determine her ballot, and she's in no rush to decide.

The triggers for how and when the undecideds will make up their minds are intensely personal.

So the campaigns have to hope to pick them off as they pursue swing groups in the most competitive states - segments of voters such as independents, seniors and white working-class voters.

People such as Donna Olson, a 66-year-old semi-retired truck driver from Oskaloosa, Iowa, who calls herself a former Democrat.

Olson expects to wait until November to make up her mind, just as she did four years ago, when her vote ultimately went to Republican John McCain.

"I don't like either one of them," Olson says of Obama and Romney. She specifically mentions Obama's support for gay marriage and Romney's proposed tax breaks for wealthy Americans.

So how will she make up her mind?

"I'm just trying to watch a little bit of everything," says Olson. "It probably will come down to November, but I'm open to see what happens between now and then."

At least Olson's tuned in to the race. One huge hurdle for both sides in the next six weeks will be getting the attention of the undecideds.

While 69 percent of likely voters report they're paying a great deal of attention to the race, the figure drops to 59 percent for persuadable likely voters. Among the larger group of all registered voters, just 31 percent of persuadables show much interest in the campaign.

That's one reason both campaigns are pouring so much money into advertising in the most contested states, and why so many ads focus on the campaign's central issue, the economy.

Persuadable voters are deeply negative about the current state of the economy. Almost two-thirds call it poor, and only 28 percent expect the economy to improve in the coming year.

That is far more pessimistic than other voters. Fifty percent of likely voters who have settled on a candidate think the economy will improve in the next year.

While the campaigns are trying lock down every vote they can - through early voting whenever possible - there's always a chunk of the electorate that's late to make up its mind.

In 2008, 4 percent of voters said they didn't pick their candidate until the last day, and they favored Obama by 5 percentage points. Another 3 percent decided in the last three days, and they skewed toward McCain. A further 3 percent decided sometime in the last week and they were about evenly divided.

In 2004, 9 percent of voters reported deciding in the last three days, and they heavily favored Democrat John Kerry over President George W. Bush, who nonetheless won re-election.

In general, the persuadables look a lot like other likely voters, and they're similarly distributed around the country, which makes it tricky for the campaigns to specifically target them. About 52 percent are male and 48 percent female. They do skew slightly Democratic.

Thirty-nine percent say they are Democrats or lean that way, 34 percent are Republican or lean GOP, and 27 percent are independent. Among all likely voters, by contrast, just 8 percent are independent and don't lean toward one party or the other.

The campaigns are intent on firming up those persuadables who already lean their way, and then hope to pick off undecided voters in the swing voter groups they're already making a priority.

The campaigns also are hoping their firm supporters can zero in on undecideds within their own spheres of influence.

As Obama frequently tells campaign crowds, "Don't just talk to people who agree with you; reach out to folks who don't follow politics that closely. Talk to somebody who's undecided."

In the same secretly recorded speech in which Romney said he had no hope of getting the support of the 47 percent of Americans who are dependent on government and back Obama, he spoke wistfully of those on the fence, saying, "What I have to do is convince the 5 to 10 percent in the center that are independents that are thoughtful, that look at voting one way or the other depending upon in some cases emotion, whether they like the guy or not, what it looks like."

Democratic pollster Stan Greenberg says truly undecided voters are particularly hard to come by this fall, attributing that to an increasingly polarized political climate and a race that ramped up unusually early, with big advertising budgets on both sides.

"There's still a fair amount of time left in this election, but the voters don't act like it," he said. "They look pretty decided."

Even independents are "more partisan in their behavior" these days, Greenberg says.

Republican pollster John McLaughlin, however, says there's still plenty of room for volatility in voters' choices, with the debates yet to come and the race especially close in certain states.

He said that to get on track after recent distractions, Romney's message to undecided voters must be a forward-looking economic pitch - not just that people aren't better off after the last four years, but that the economy will be much better off after four years under Romney.

Overall, the race is neck-and-neck in the AP-GfK poll, with 47 percent of likely voters supporting Obama and 46 percent for Romney.

While 84 percent of likely voters overall think it's been easy to make a decision this year, the undecideds, unsurprisingly, are having a far tougher time. Fifty-six percent of persuadables report having difficulty choosing sides.

Michael McGeehan, a 22-year-old from Salem, Ore., thinks that's the way it should be.

McGeehan is leaning toward Obama but says anything is possible because "things can happen." He adds: "There's a lot of people who have their minds made up too far in advance."