(CNN) -- Gov. Sarah Palin on Wednesday said Sen. Barack Obama has ties to a Columbia University professor who she said is "a former spokesperson for the Palestinian Liberation Organization." The Obama campaign said on its Web site that "ugly insinuations about Barack Obama's relationship with a former neighbor and university colleague ... are completely false." The professor has denied he was a spokesman for the Palestine Liberation Organization. Palin said her assertion "is not negative campaigning to call someone out on their record." "It seems that there is yet another radical professor from the neighborhood who spent a lot of time with Barack Obama going back several years," Palin said at an event in Bowling Green, Ohio.
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NEW: Gov. Sarah Palin says Sen. Barack Obama has ties to ex-"PLO spokesman"
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NEW: Obama says John McCain calling him "every name in the book"
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Ex-President Clinton joining Obama for late-night Florida rally
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New McCain ad makes fun of Obama's prime-time TV spot
Palin said she and @placeholder are determined to put the country on "a path toward energy independence" and charged that an Obama administration would hinder that process.
The spot, which is estimated to have cost about $5 million, includes a live segment from @placeholder, with voters discussing their problems and Obama laying out his plans for the country.