Soul legend Aretha Franklin will once again perform for President Obama, this time at his Labor Day rally taking place Monday at Hart Plaza in Detroit.  Franklin performed at a 2008 rally during Obama's campaign, also at Hart Plaza, then sang at his inauguration in Washington, D.C in January 2009.  She says she will sing three of her signature hits, including "Chain of Fools."  Check out a clip of the "Queen of Soul" performing the classic with Mariah Carey below.