Ramba uchinyora ndima iyi - Muna 2008, Díaz akava purezidhendi weU.S. Conference of Mayors. Semunhu akazvimirira, uye aimbove akanyoreswa Democrat, Diaz akataura pa2008 Democratic National Convention ndokutsigira kukwikwidza kwaObama semutungamiri wenyika
. Kutevera kusarudzwa kwaObama, Diaz akafungidzirwa kuti ave munyori weHHS; nzvimbo yacho yaizopedzisira yaenda kuna Kathleen Sebelius.