WASHINGTON (AP) Three months before Election Day, John McCain's stepped up aggression begs the question: Will voters vote for the scold?

A new ad launched Wednesday suggests Democratic rival Barack Obama is nothing more than a lightweight celebrity akin to a Britney Spears or a Paris Hilton. A previous ad took issue with Obama's canceled visit to injured troops. McCain has suggested Obama would rather lose a war than an election and ridicules him for the "audacity of hopelessness" in his Iraq policies.

"He's the biggest celebrity in the world," his latest ad asks. "But, is he ready to lead?"

Some Republicans welcomed McCain's confrontational strategy. New Hampshire GOP Chairman Fergus Cullen said Republicans in his state "like to see the McCain campaign on offense."

But in striking an aggressive pose, McCain is in danger of letting the caricature of an angry, petulant candidate take seed -- not so much because he is one, but because it stands in stark contrast to Obama's carefully cultivated, well, celebrity, and McCain's own promises to run a respectful campaign.

"The campaign is making him seem angrier than he is and therefore it's a disservice to him," said John Weaver, McCain's former senior strategist, who left the campaign in a shake-up last year.

Angry candidates don't win elections. Ronald Reagan and Bill Clinton won by running as sunny optimists -- one promised John Winthrop's "shining city upon a hill" and the other was the "man from Hope."

But McCain wants the presidential campaign to be about Barack Obama -- that's why he talks about him so much.

To that end, McCain is helping frame a not-so-flattering portrait of Obama for voters. His ads have become increasingly tough; a third of his commercials portray Obama negatively, a new study concluded.

Obama is projecting confidence, but he is not ready to ignore McCain.

In back-to-back days, he has retaliated with ads attacking McCain. In both, he accuses McCain of engaging in "old politics" -- a loaded phrase given that McCain turns 72 in late August.

Obama offered a personal rejoinder Thursday. "So far all we've been hearing about is Paris Hilton," he said, campaigning in Iowa. "I do have to ask my opponent: Is that the best you can do? Is that what this election is really all about? Is that worthy of the American people?"

Polls show that the race remains tight nationally and in key battlegrounds. New state polls by Quinnipiac University show Obama leading McCain in Pennsylvania, and McCain and Obama tied in Ohio and Florida.

No doubt Obama has fame. He fills political venues with people. He breaks fundraising records with a massive donor base. He does not have a name recognition problem. But Obama himself concedes that his challenge is getting voters to see him as president.

"It's a leap, electing a 46-year-old black guy named Barack Obama," he said Wednesday.

He also said McCain and his Republican allies will try to scare them by saying Obama, who is black, "doesn't look like all those other presidents on the dollar bills."

McCain campaign manager Rick Davis on Thursday said Obama, with that comment, had "played the race card." He said the remark was "divisive, negative, shameful and wrong."

In working to sow doubts about Obama, McCain and his campaign have worked on a specific story line that the Democrat is not tested, not ready to lead and too out of touch with the public.

As of last week, more than 90 percent of the ads aired by Obama did not mention McCain, whereas one-third of McCain's ads referred to Obama negatively, according to a study of political commercials by the Advertising Project at the University of Wisconsin.

For his part, Obama has managed to keep his hands cleaner on negative ads, though he has counter-punched. Instead, outside groups that support him have run commercials against McCain. On Thursday, a coalition including MoveOn.org and the Sierra Club was launching ads critical of McCain's stance on energy and gasoline prices.

For all the campaign's talk of Obama's celebrity, McCain is popular in his own right. He ran for president in 2000 and has built his image as a maverick, challenging President Bush and fellow Republicans on some high-profile legislation. Some Republicans worry that a negative campaign will undermine his appeal, particularly with independent voters.

Others maintain that as long as Obama is the candidate who needs to prove himself, voters will pay little attention to McCain -- angry or not.

"John McCain is simply not a relevant variable in this election," said Ken Goldstein, a University of Wisconsin political scientist and director of the advertising project.

In building their case against Obama, the McCain campaign has employed several lines of attack. It's heaviest ad placements have focused on energy, blaming Obama for high gas prices and depicting him as a tax raiser who opposes expanded oil exploration. But it also has launched ads criticizing Obama's stand on the Iraq war and his decision not to visit wounded soldiers in Germany. Obama said he did not want the visit to be seen as political.

The Iraq ads have received widespread media attention, although they appeared only a handful of times in a few markets.

"This careening from message to message makes them look like they don't have one specific thing they want to say about this guy and that there is no centralized theme, there is no centralized message," Republican pollster Tony Fabrizio said. "And that is most concerning."

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EDITOR'S NOTE - Jim Kuhnhenn covers presidential politics for The Associated Press.