Mr. Obama's cryptic remark came at a fund-raiser in Houston in which he dared his rival to tell the truth about the brouhaha, declaring, "You can't handle the truth!"
The Illinois senator also told his supporters that Mrs. Clinton was trying to use the plagiarism allegations to back him into a corner, warning that "Nobody puts Baby in a corner."
Obama, who exhorted the crowd at the fundraiser to "show me the money," seemed dismissive of Clinton's accusations, later telling MSNBC's Andrea Mitchell, "Frankly, my dear, I don't give a damn."
Professor Davis Logsdon, who studies plagiarism in the speeches of presidential candidates at the University of Minnesota's School of Public Oratory, says that accidental plagiarism can often occur in the hurried atmosphere of a political campaign: "As Obama himself has often said, he feels "the need ... the need for speed."
For his part, Obama seems to have moved past the controversy altogether, greeting his audience at a campaign rally in El Paso with his trademark welcome: "Hello, I'm Johnny Cash."
Elsewhere, President George W. Bush said that while he recognized Kosovo, he could not recognize Kosovo on a map.