John McCain has unleashed a withering television commercial interweaving clips of Paris Hilton and Britney Spears with footage of Barack Obama addressing 200,000 Germans in Berlin a week ago in an apparent attempt to portray the Illinois senator as a bimbo celebrity with more smile than substance.
The spot, aired in 12 battleground states, was another sign of the McCain campaign sharpening its attacks on Mr Obama. "He's the biggest celebrity in the world, but is he ready to lead?" the voiceover asks, going on to question his positions on offshore oil drilling and tax policy.
This latest assault, honed in part by a new team of advisers last seen guiding George Bush's often acid re-election strategy against John Kerry four years ago, also hints that Mr McCain has forgone promises he once made to maintain a new level of civility in the White House race.
Mr Obama, who has been in Missouri and Iowa this week addressing far more modest crowds than he drew in Berlin, responded with a TV ad accusing Mr McCain of taking the "low road". "John McCain," it declared. "Same old politics. Same failed policies." Mr Obama said that he had "never even met the woman", meaning Hilton.
A spokesman for the hotel heiress said: "Miss Hilton was neither asked, nor did she give permission, for the use of her likeness in the ad, and has no further comment."
The Obama campaign has also spoken out against one of the candidate's own supporters, the rapper Ludacris, who released a song using an expletive to describe defeated Democratic contender Hillary Clinton. He also says Mr McCain doesn't belong in "any chair unless he's paralysed". Mr Obama's spokesman, Bill Burton, described the song as "outrageously offensive".
Mr McCain is trying to exploit a wariness among many voters about what Mr Obama really stands for. The Obama campaign, meanwhile, will seek to portray Mr McCain as a mean-spirited grouch – Democrat leaders are already dubbing him "McNasty" – who is falling back on negative tactics.
Some Republicans seem queasy about the direction that Mr McCain's new advisers are taking. Andrea Tantaros, a party strategist, told MSNBC his latest ad was "absurd and juvenile".
David Axelrod, the top strategist for Mr Obama, said: "When people are struggling... trying to pay bills... I don't think they have much tolerance for Britney Spears and Paris Hilton. I think they understand times are more serious than that, and they thought John McCain was too."
But after a long period of Mr Obama hogging the media canvas, Mr McCain's team seems to have hit something of a stride with ads that may be unfair and unsubtle but are at least getting him fresh press attention.
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