Former Senator (N.C.) has been accusing his rival Sen. (N.Y.) of double-talk for a week, since she refused to say clearly whether illegal immigrants should get driver's licenses - but his own position on the issue is also incoherent, experts say.
Immigration policy experts on both sides of the debate say they're puzzled by Edwards' stance, which appears to hinge on blurring the distinction between state and federal powers.
"He supports licenses as part of a path to citizenship. He doesn't support the Spitzer plan because it doesn't include a path to citizenship," said Edwards' deputy campaign manager Jonathan Prince in an e-mail referring to the New York governor's plan that prompted the question that flummoxed Clinton.
"That's not a rational position - Eliot Spitzer couldn't ever offer somebody a path to citizenship," said Margie McHugh, the Co-Director of the National Center on Immigrant Integration Policy at the Migration Policy Institute, which favors immigration reform.
"I don't know if they think you're stupid or what they think," said Frank Sharry, the executive director of the National Immigrantion Forum, another broadly pro-immigration policy shop.
Sharry laughed aloud when read Prince's statement of Edwards' position.
That is "sort of like saying I oppose the confederate flag in Southern states because there's not a corresponding flag burning amendment to it. It's nonsensical," Sharry said.
Indeed, opposing Spitzer's plan on those grounds amounts to de facto opposition to any driver's licenses for illegal immigrants, something Edwards and his aides have not previously stated.
That's a dramatic shift from Edwards' stand in 2004, when he told "Hardball's" Chris Matthews, "I'm for it," when asked about licenses for illegal immigrants.
Edwards may be changing his position to court working-class Iowa voters, among whom illegal immigration is an emotionally charged issue.
However, his effort to soft-pedal the change seems aimed at a party establishment that is resisting populist anti-immigration forces, and hopes to win the vast bulk of the Hispanic vote in the general election.
In Philadelphia last week, moderator Tim Russert asked the seven Democratic candidates, "Does anyone here believe an illegal immigrant should not have a driver's license?"
Connecticut Sen. was the only one to indicate opposition.
In the wake of the debate, Edwards aides told reporters that he favors driver's licenses for illegal immigrants, but opposes Spitzer's plan for other reasons.
They did not say that he opposes all efforts to extend licenses to illegal immigrants unless taken in the context of "some future comprehensive reform."
He and his campaign appear not to have been asked that question directly.
"Two of Mrs. Clinton's opponents, Senator Barack Obama and John Edwards, support granting licenses to illegal immigrants, although Mr. Edwards has problems with elements of Mr. Spitzer's proposal," The New York Times reported Nov. 1.
Politico reported that an Edwards aide "said after the debate that Edwards also supports issuing licenses to illegal immigrants, which is the most controversial element of Spitzer's plan."
In an interview Sunday on "This Week," Edwards also seemed to limit his opposition.
"You wouldn't give them a driver's license?" asked host George Stephanopolous.
"Not under those circumstances, not if they have an opportunity to become an American citizen and they're choosing not to," Edwards replied, referring to the federal legislation which has not passed.
Prince said Wednesday that Edwards does, in fact, oppose any state attempt to give licenses to illegal immigrants under existing federal law.
But for state plans to include a path to citizenship "would be imossible," said Angela Kelley, the director of the Immigration Policy Center at the American Immigration Law Foundation.
"The drivers licenses will be issued by a state entity. The states are pre-empted."
Clinton has avoided taking a clear position on the New York policy, though she expressed support for the quandary in which governors find themselves.
Illinois Sen. , meanwhile, said he favored Spitzer's plan.
Kelley said some of the murkiness around the issue is understandable.
"These are such complex issues and the candidates are clearly struggling both to understand the policy and to walk a tightrope on the politics," she said.
Meanwhile, other immigration experts are still struggling to understand the details of the candidates' stances.
"Hillary seems unable to give an answer, and it's hard to say that Edwards' answer is all that clear," said Steve Camarota, the policy director of the Center for Immigration Studies, which lobbies to restrict immigration and opposes drivers licenses for illegal immigrants.
"Obama has the one clear answer: give them drivers licenses."