I've been wrong before, but scuttlebutt around DC was that
former New Mexico Governor Bill Richardson endorsed Obama--and "betrayed" the Clintons--in exchange for serious consideration as Vice Presidential running-mate. Calculation: He should secure the Hispanic vote safely in the (D) column; he has legislative experience as a congressman; executive experience as a governor and cabinet officer (Secretary of Energy); and international experience as UN ambassador during the Clinton Administration. Oh, and he's run for President, too...