If Democrat John Kerry (search) has a chance of winning the White House, he must win over many in the small but central slice of the electorate known as "persuadable" voters who harbor serious doubts about his leadership abilities.

They tend to like Kerry better on handling the economy and half say a fresh start would be worth the risk. But doubts about his leadership skills are mentioned early as an obstacle to those considering a switch to the Democratic nominee.

An Associated Press poll of 1,329 persuadable voters highlighted the difficult task facing Kerry in the dwindling weeks of the presidential campaign.

About one in every five voters is persuadable — including about 5 percent who tell pollsters they don't know who will get their vote and about 15 percent who say they are leaning toward one candidate but could switch to another.

The number of persuadable voters has been as high as one-third in recent presidential elections, but voters chose sides early in this campaign after the close 2000 contest, the Sept. 11 terror attacks and the Iraq war.

Among all persuadable voters — the undecided and the leaners — Bush has a lead of 40 percentage points on the question of who would best protect the nation.

"I've been thinking about the scare tactics (Vice President) Cheney and them are using," said James Willis, of Ayden, N.C., about GOP warnings that electing Kerry would be dangerous for the country. "It makes you wonder about turning the country over to a new person."

Kerry faces Bush in the first presidential debate Thursday night at the University of Miami and both will get a chance to outline their stance on foreign policy.

"I'm glad to see Kerry's finally speaking up," said Darlene Wood, a 42-year-old voter from San Jose, Calif., who leans toward Kerry. "I think Bush has been far more misleading and critical in his campaigning than Kerry had been. Now Kerry's taking more of the same aggressive tack, fighting fire with fire."

While vulnerable on foreign policy, Kerry holds a 2-to-1 advantage among persuadables on who would best create jobs. The Democrat has lost his advantage on the jobs issue in polls of all likely voters.

"I wish they'd quit slamming each other and let me know what they're going to do," said Wanda Ramsey, an undecided voter from Owasso, Okla. "I want to hear more about health care for the poor and the elderly."

Like many of the persuadable voters, she also wants Kerry to spell out his plans for Iraq.

Concerns about Kerry's leadership abilities in areas like fighting terrorism and the Iraq war are frequently mentioned by those pondering a switch to Kerry.

By contrast, when undecided voters and others say what might block them from switching to Bush they are quick to mention differences with him on issues. For many, those concerns certainly include Iraq policy.

Six in 10 persuadable voters say sending troops to Iraq was a mistake — a higher level of concern than among the electorate generally.

But they favor Bush over Kerry on the question of who would best handle the situation in Iraq, 52 percent to 41 percent, roughly the same as all likely voters.

In the AP polling, 1,329 people were first interviewed Aug. 31 to Sept. 2 and then re-interviewed Sept. 21-27. In the initial screening, 18 percent said they didn't know who would get their vote, with the rest evenly split between leaning Kerry or leaning Bush. The follow-up interviews found that 13 percent of the 1,329 had become committed to Bush and 11 percent to Kerry. That left 937 people who said they were still persuadable.

On personality traits, only 32 percent of persuadable voters consider Kerry decisive while 79 percent attribute that quality to Bush. That tracks with polls of all likely voters.

Some 42 percent of persuadable voters say Bush is honest, considerably lower than he rates among all likely voters.

"I'm not inclined to support either one of those guys," said Gregory Wemhoff, a military retiree from Bremerton, Wash. "I will be holding my nose when I vote."

The survey had a margin of error of plus or minus 2.5 percentage points for the initial sample of 1,329 persuadable voters, and plus or minus 3 percentage points for the subgroup of 937.

AP and Knowledge Networks will resurvey voters in mid-October.