The race to replace Barack Obama as Illinois' junior senator heated up Tuesday as Rep. Bobby Rush, D-Ill., called on Gov. Rod Blagojevich to name a black man or woman to the seat. By invoking race, Rush, who is black, drove a potential wedge between the prospective white and black contenders for the seat. Rush said it would be a "national disgrace" if Obama's seat were not filled by an African American.