CEDAR RAPIDS, Iowa — John McCain's campaign accused Barack Obama on Thursday of playing racial politics a day after the Democratic candidate predicted Republicans would try to scare voters by pointing out "he doesn't look like all those other presidents on the dollar bills."

After months of contending that their campaigns would eschew personal attacks as part of a new kind of politics, the presumed presidential nominees turned nasty over what Obama meant when he said McCain and other Republicans would try to scare voters by pointing out that the Democratic candidate "doesn't look like all those other presidents on the dollar bills."

McCain took on the role of aggrieved victim, his campaign waiting almost a day after Obama's remarks to charge that he had injected race into the presidential campaign. "Barack Obama has played the race card, and he played it from the bottom of the deck. It's divisive, negative, shameful and wrong," McCain campaign manager Rick Davis said.

Obama, smarting from McCain's constant thumping about a first-term senator's thin resume wrapped inside a charismatic speaking style, countered that being black had nothing to do with his prediction of the nature of attacks yet to come. However, comparing his looks to those of presidents on U.S. currency — all white men — gave his opponents a chance to say the man who would be the first black president was subtly charging racism.

Not so, Obama's campaign said, explaining that Obama was referring only to being new to Washington politics.

"Barack Obama in no way believes that the McCain campaign is using race as an issue, but he does believe they're using the same old low-road politics to distract voters from the real issues in this campaign, and those are the issues he'll continue to talk about," Obama campaign spokesman Bill Burton said.

Obama on Wednesday told a gymnasium full of people in Springfield, Mo., that McCain and President Bush will resort to scare tactics to maintain their hold on the White House because they have little else to offer voters.

"Nobody thinks that Bush and McCain have a real answer to the challenges we face. So what they're going to try to do is make you scared of me," Obama said. "You know, 'He's not patriotic enough, he's got a funny name,' you know, 'He doesn't look like all those other presidents on the dollar bills."'

While calling to mind the images of presidents on the nation's paper money — George Washington, Abraham Lincoln, Andrew Jackson and Ulysses S. Grant are on the bills most commonly used — Obama didn't make clear what distinctions he thinks McCain is likely to raise. Besides being white, they were for the most part much older than Obama when elected.

McCain has not raised Obama's race as an issue in the campaign; he has said that Obama lacks experience.

When asked by The Associated Press what Obama meant by the comparison, Obama strategist Robert Gibbs said Thursday morning that the senator was not referring to race.

"What Barack Obama was talking about was that he didn't get here after spending decades in Washington," Gibbs said. "There is nothing more to this than the fact that he was describing that he was new to the political scene. He was referring to the fact that he didn't come into the race with the history of others. It is not about race."

Obama often makes references to his distinctions as a candidate, such as saying there are doubts among some voters because he has "a funny name." At times he refers to his race as well, saying he looks different from any previous candidate but then adding that the differences are not just about race. Addressing supporters Tuesday night at a fundraiser in Springfield, he said, "It's a leap, electing a 46-year-old black guy named Barack Obama."

The exchange over race comes a day after the McCain campaign launched a negative television ad that suggested Obama was similar to lightweight celebrities Britney Spears and Paris Hilton.

Obama argued on Thursday that he's putting substantive issues on the table, while McCain is offering distractions.

"So far all we've been hearing about is Paris Hilton," Obama said. "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."