Washington (AP) One of those democrats known as “superdelegates” is switching his alliegance from Hillary Clinton to Barack Obama.

Joe Andrew was appointed chairman of the Democratic National Committee by Clinton's husband in 1999. He had announced his support for the New York senator last year on the day she declared her candidacy for the White House.

Andrew holds a news conference in his hometown of Indianapolis today to urge support for Obama in Tuesday's Indiana primary, one of the few remaining prizes on the democratic calendar.

He's also writing a letter to other superdelegates urging them to heal the democratic rift and unite behind Obama. Andrew tells the Associated Press he's become convinced that the continuing political fight has become bad for the democratic party.

In his letter, Andrew says the party battle is doing John McCain's work for him and has become a distraction from the issues that really matter to Americans.