Beverly Fanning who was joining Bush on Sunday night at a fundraiser gala at Washington's Ford's Theatre (scene of Abe Lincoln's assassination on 14 April 1865) says she is also volunteering for Obama's presidential campaign.

There are lots of other converts. One of the most famous is Julie Nixon Eisenhower, daughter of Tricky Dick himself as well as the wife of President Dwight Eisenhower's grandson; Connie Ballmer, wife of Microsoft Chief Executive Officer Steve Ballmer; Ritchie Scaife, the estranged wife of conservative tycoon Richard Mellon Scaife and the famous boxing promoter Don King.

They are mostly "moderate Republicans or independents who are dissatisfied with the direction of the country now and are looking for change," Professor Anthony Corrado tells McClatchy. "There is a large block of Republicans, particularly economic conservatives, who just feel that the Republican Party in Washington completely let them down" by failing to control spending and address other problems, he said. "The Republicans have really given these donors no reason to give."