PRESIDENTIAL PARTNERS President Barack Obama dances with Air Force Staff Sgt. Bria Nelson, and First Lady Michelle Obama dances with Marine Corps Gunnery Sgt. Timothy Easterling during the Commander In Chief's Ball in Washington, D.C., Jan. 21, 2013. SHARE: Download: Full Size (0.06 MB) Credit: VIRIN: 656874-P-IMC97-991.jpg Photo Gallery