"Giuliani, I definitely don't trust him as far as I can throw a bull elephant by his tail," said Little, the Georgia retiree. "John McCain, I don't like him."

It is unclear whether Thompson will enter the race for the Republican nomination. He revealed Wednesday that he had been diagnosed in 2004 with lymphoma, which his physician said was in remission after treatment.

Many of the actor's backers say that their second choice for president is Giuliani.

"He's also a person who was able to clean up and operate New York," said Patrick Ary, a radio announcer in Wichita, Kan., whose first choice for president is Thompson. "If you can succeed in New York City, you can do it almost everywhere."

Bad news for Edwards

When Democrats were asked to assess their own broad field of potential candidates — including former Vice President Al Gore, who has not said he will run — Clinton drew support from 33% of respondents. Obama drew 23% and Edwards 14%. Gore, enjoying a burst of publicity surrounding a documentary on global warming that features him, was backed by 13%.

When the choice was limited to the top three candidates, support for Clinton jumped to 42%, whereas Obama drew 32% and Edwards 20%.

The demographic breakdown of supporters spells bad news for Edwards, the son of a textile worker and who represented North Carolina in the Senate. Although his Southern roots and his pitch to working-class voters would seem to make minorities a natural constituency for him, the poll found he drew limited support from blacks.

In a three-way contest, 50% of black respondents supported Clinton, whereas 41% supported Obama.

"I can't say that just because he's black, I'm going to vote for him," said Kay Harris, an African American retiree in Chicago who favors Clinton. "She has experience. She was around her husband at the time [he was president]. Being a smart woman, she picked up a lot of knowledge."

Ken Hoskins, another black voter, said he favored Obama — not because of his race but because of his challenge to the status quo in national political culture.

"I think today's climate calls for a fresh approach," said Hoskins, a real estate consultant in Virginia. Indeed, Obama's message of political reform seems to be most appealing to upscale voters like Hoskins.

Obama outpolled Clinton in higher-income groups. But Clinton won support from 52% of voters with household income under $40,000, compared with 26% for Obama and 16% for Edwards. Though Obama ran even with Clinton among college graduates, Clinton did better among less-educated voters.

Clinton also enjoys a big advantage among women. In a three-way race, 44% of women backed Clinton, compared with 29% for Obama and 21% for Edwards.

Edge for Democrats?

When all voters were asked whether they would prefer a Republican or Democrat to be elected president in 2008, 49% favored Democrats, compared with 39% favoring the GOP.

But when they were asked to assess particular candidates, voters did not give such a decided edge to Democrats.

Many of the matchups were so close that the margins were statistically insignificant, including the choice between Clinton and McCain, in which the Democrat drew 45% and the Republican 42%. Giuliani was a more formidable opponent for Clinton, drawing 48% to her 42%. Of the Democratic candidates, only Obama outpolled Giuliani, 46% to 42%.

The poll also provides a window into the different concerns voters are bringing to the campaign. Almost two-thirds of Democratic voters said the war in Iraq was the most important issue for candidates to address, whereas only 37% of Republicans cited Iraq as the top priority.

Among GOP voters, 13% wanted the candidates to call for tougher immigration laws. By contrast, only 1% of Democrats gave priority to an illegal immigration crackdown.