Vice President Joe Biden is interviewed by NPR's Robert Siegel in the Secretary of War Suite of the Eisenhower Executive Office Building, Dec. 13. David Lienemann/The White House hide caption

itoggle caption David Lienemann/The White House

Vice President Joe Biden smiles after filing papers for President Obama to be on the N.H. primary ballot. (AP Photo/Jim Cole)

Jim Cole/AP hide caption

itoggle caption Jim Cole/AP