Elsewhere, however, it is hard to find many areas where they disagree on their approach to foreign policy or national security issues. The reason could be that their advisers are largely made up of people from Bill Clinton's administration.

Hillary's team includes former Secretary of State Madeleine Albright, former U.N. Ambassador Richard Holbrooke, and former National Security Adviser Samuel Berger, who was caught red-handed, stealing classified Clinton documents from the National Archives.

Mr. Obama's advisers include former National Security Adviser Anthony Lake; Susan Rice, an assistant secretary of state in Mr. Clinton's second term; and Jimmy Carter's national security adviser, Zbigniew Brezezinski.

"If you add up all of their differences, they both fail on Iraq. They both are advocating a policy that unless significantly modified would lead to a reversal of all our military progress in 2007," Mr. O'Hanlon said.