WASHINGTON -- Both John McCain and Barack Obama are promising a high-minded White House campaign. But the dirt is already being dished, and could be spread by the bucketload soon.
"It's going to be Swift Boat times five -- on both sides," one unidentified McCain insider was widely quoted as saying, anticipating a November matchup with Obama when and if Hillary Clinton bows out of the Democratic race.
The 2004 presidential election between George W. Bush and John Kerry set a new standard for campaign mudslinging when the Democrat's Vietnam War record was impugned by a right-wing group called Swift Boat Veterans for Truth.
Before that, during his unsuccessful primary campaign against Bush in 2000, McCain was rumored to have fathered an illegitimate black child.
The child, in fact, was a Bangladeshi orphan adopted by the Republican senator and his wife Cindy. But enough of the mud clung to smother McCain's hopes in South Carolina and allow Bush back into the year's primary race.
This time, the presumed Republican nominee has a "rapid response squad" to nip scurrilous rumors in the bud.
The African-American Obama has a similar operation, but has been powerless to prevent the spread of emails portraying him as a secret Muslim.
Those false rumors have continued to do the Internet rounds even as Obama has battled to fend off incendiary sermons by his former Christian pastor, Jeremiah Wright, which look certain to come back in the form of attack ads.
Those ads will not necessarily come from official Republican quarters but from shadowy "527" groups of the Swift Boat variety, named after the section of the US tax code that governs their political activity.
The Democrat could also be tarred by his links in Chicago to William Ayers, an ex-member of the anti-Vietnam War group Weather Underground, which bombed government premises from the late 1960s.
Obama's patriotism, and that of his wife Michelle, meanwhile has been the subject of vitriol on the powerful conservative talk radio circuit for months, and already featured in attack ads by the Tennessee Republican Party.
McCain may eschew the low road of campaigning, but Obama has already accused him of one "smear" for remarking that the Democrat is the favored candidate of the Palestinian extremist group Hamas.
That suggestion prompted Obama to accuse McCain of "losing his bearings" -- which the Republican's campaign took to be a veiled reference to his age. At 72 next January, McCain would be the oldest president elected to a first term.
The age question is likely fodder for anti-McCain ads, along with his entanglement in a 1980s corruption scandal as a member of the so-called Keating Five group of senators.
The Republican's temperament could provide ample material too. A series of expletive-laced rants by McCain against Senate colleagues featured in a Washington Post story last month.
"His temper would place this country at risk in international affairs, and the world perhaps in danger," former Republican senator Bob Smith told the newspaper, in words sure to be spliced into any attack ad on the issue.
And evoking Kerry's Swift Boat treatment, McCain is the target of YouTube videos alleging he received special treatment from his Vietnamese captors in the infamous "Hanoi Hilton" and "betrayed" fellow US prisoners of war.
Former White House adviser William Galston of the Brookings Institution noted the promises of civility from Obama and McCain.
"Does that mean a civil campaign? Not necessarily," he told AFP, noting that McCain will be far more reliant than the lavishly funded Obama on surrogate spending by outside groups.
"So the potential role of the Republican Party and 527 groups filling in gaps for the McCain campaign might be extensive," Galston said.
But would harshly negative attacks work this time round? Obama thinks not.
In Iowa Tuesday, after taking another stride to defeating Clinton by clinching a majority of elected Democratic delegates, he predicted that Republicans would try "yesterday's tactics" to stay in power.
"Well they can take the low road if they want, but it will not lead this country to a better place. And it will not work in this election," he said. "It won't work because you won't let it. Not this time. Not this year."
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