In other campaign news, Senator Obama says he’s accepted Senator Hillary Clinton’s explanation for controversial comments invoking the 1968 assassination of Robert F. Kennedy to justify her continued stay in the Democratic presidential race. In an interview in South Dakota Friday, Clinton cited Kennedy’s assassination as an example of a contest continuing through June.

Sen. Hillary Clinton: “My husband did not wrap up the nomination in 1992 until he won the California primary somewhere in the middle of June, right? We all remember Bobby Kennedy was assassinated in June in California. You know I just — I don’t understand it.”

Clinton explained she was trying to cite a historical precedent for a June presidential contest. While not apologizing for the remark, Clinton did say, “I regret that if my referencing that moment of trauma for our entire nation and in particular the Kennedy family was in any way offensive.” The Obama campaign initially criticized Clinton for invoking the assassination of a candidate. Obama has received Secret Service protection since the early stages of his campaign.