The endorsements were announced Friday along with word that media mogul Oprah Winfrey and Caroline Kennedy, the daughter of President John F. Kennedy, would campaign for Obama in California, the Chicago Tribune political blog, "The Swamp" reported.

California is the biggest prize of the 22 states holding Democratic primaries or caucuses Tuesday.

In its endorsement, the Times called Obama, a freshman senator from Illinois, an inspiring leader who "appeals to Americans long weary of divisive and destructive politics."

In her endorsement in The Washington Post, Susan Eisenhower, a Republican, said she backed Obama because he would lead as her grandfather did and "leave America a better, stronger place."