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The campaign for the vice presidency has been rife with "Where's Waldo" jokes lately, as Dick Cheney (search), the Republican incumbent, and John Edwards (search), the North Carolina Democrat who wants his job, have taken a back seat to President Bush and John Kerry.

But interesting dynamics that could be key to the election have, in fact, been playing out dramatically behind the vice presidential candidates' vigorous schedules of town hall meetings, rallies and state fair speeches in battleground states across the country.

Edwards has been considerably more "invisible" than Cheney, who has been quoted more liberally by the national press for his pointed verbal hits against the Kerry campaign.

"Cheney has changed and has become more aggressive and a kind of attack dog," said Juan Williams, FOX News Channel contributor and correspondent for National Public Radio.

But Edwards, while campaigning more quietly than Cheney, has been no less energetic. Both men routinely cross each other's paths — even stumping in the same state at the same time, as happened last week when both candidates paid visits to the battleground states of Ohio and West Virginia.

"[Edwards has] been in 34 states — two or three cities a day in key markets within battleground states," said his campaign spokesman, Mark Kornblau. "It's true Cheney has been making headlines in the last few weeks, but I don't think it's the kind the White House wants, or any campaign wants."

Some political opinion makers say Cheney has become a more effective candidate than Edwards, mainly because he has gone on the offensive, driving the GOP base wild with appreciation, while distracting Kerry's campaign to no end.

"He is an irritant to the Kerry campaign. He has drawn the wrath of (Democratic National Committee Chairman) Terry McAuliffe (search), he has drawn the wrath of John Kerry — when they should be going after President Bush," said Bill Whalen, research fellow with the Hoover Institution at Stanford University.

Whalen said Cheney has embraced the vice president's time-honored role of "hatchet man" in the closing days of the campaign, saying the things Bush couldn't possibly say and taking the heat with little political consequence, because after all, he's the number two. "Every day spent bashing Cheney is one less day bashing Bush," Whalen said.

Take, for instance, Cheney's remarks earlier this month when he suggested at a town hall meeting in Iowa that the United States might be vulnerable to an even more devastating terror attack if a "wrong choice" is made in the Nov. 2 election. For several days afterward, Democrats bombarded Cheney with calls to detract his statements.

"To me, that is a very effective thing for a vice presidential candidate to do," Whalen said. "It distracts the Democrats and throws them off their game."

Bush, meanwhile, would not comment on Cheney's remarks, other than to say his running mate was underscoring the "differences between the two candidates on the War on Terror."

"It's the good-cop, bad-cop routine — it's a traditional thing for the vice president to be the tough guy and let the president look more presidential," said Gary Jacobson, professor of political science at the University of California at San Diego. "There isn't a word that isn't scripted."

But not everyone thinks Cheney's attack-dog strategy is a winning one.

"I think that Cheney detracts from the Bush campaign," said Jim Stimson, political science professor at the University of North Carolina at Chapel Hill. "Maybe the Republicans would rather Cheney be invisible."

Kornblau said Cheney's comments represent a form a desperation. "They can't run on their record," he said, "so they have to resort to these scare tactics."

Nonetheless, it is Cheney's opponent, Edwards, who is drawing criticism for being "missing" or, worse, "invisible" these days, partly because he has not been more aggressive, say observers, leaving the national media is disinterested.

"People are saying, where is John Edwards?" said Whalen.

The problem, said Williams, is that while Cheney is filling out the role as bad cop, Edwards is playing the role he was selected to play — the upbeat, charming, positive cheerleader for his team. He has been sent out to connect with voters and rally the base. To ask him to transform into attack dog might be asking too much, and might not help his reputation.

"That guy is working his butt off, there's no question about that," said Williams. "In terms of saying the kind of bumper sticker slogans that will really hang around your opponent's neck, I don't think that's the kind of guy they selected."

Jacobson agrees. "He's kind of an upbeat, positive guy," he said. "He can't be turning into Dracula for the campaign. So he's doing what we knew he would be doing.

"No one should be surprised that Edwards is being Edwards and he's sticking to his theme."

But Whalen said it's a mistake to be the nice guy. "In 1996 you had (Vice President) Al Gore out there as a pit bull" [in the Clinton administration]," he said. "Jack Kemp wouldn't play that role as Bob Dole's vice presidential candidate, and it hurt him."

Edwards stepped up the rhetoric on Thursday when he filled in for Kerry at a campaign rally for women voters in Davenport, Iowa. He said Bush "needs to come back to earth" and begin telling the American people the truth about Iraq, for which he said, "things are going worse and worse."

Kornblau said Edwards can remain positive while making pointed criticisms of his opponents. "I would argue that he has been making a more cogent and direct indictment of the opposition than his opponent — he's not 'stepping in it' in order to make some headlines."

Meanwhile, Cheney told an audience Thursday he was, "appalled at the complete lack of respect Sen. Kerry showed" for Iraqi Prime Minister Ayad Allawi (search) when he questioned whether Allawi was being entirely truthful in his assessment of the war.

Anne Womack, Cheney campaign spokeswoman, said the vice president's job is to underscore the policy differences between Bush and Kerry, particularly on the War on Terror — and she said Cheney has done an effective job.

"It's one of the central issues of the campaign — that we can fight a more effective and aggressive war on terror," she said.

On the question of whether Cheney comes off as too foreboding or tough, Womack said: "The vice president is a serious individual, and he talks about serious issues. We think that's an asset and the American people see that as an asset, too."