Former state and national Democratic Party Chairman Joe Andrew announces at a news conference in Indianapolis, Thursday, May 1, 2008 that he has switched his allegiance to Barack Obama and is encouraging fellow Democrats to "heal the rift in our party" and unite behind the Illinois senator. (AP Photo/Michael Conroy)

Former state and national Democratic Party Chairman Joe Andrew announces at a news conference in Indianapolis, Thursday, May 1, 2008 that he has switched his allegiance to Barack Obama and is encouraging fellow Democrats to "heal the rift in our party" and unite behind the Illinois senator. He also has written a lengthy letter explaining his decision that he plans to send to other superdelegates. (AP Photo/Michael Conroy)