Lt. Gov. Gavin Newsom says he won't run for the US Senate when Barbara Boxer retires next year. Neither will current LA Mayor Eric Garcetti. But former Mayor Antonio Villaraigosa is back on Facebook for the first time in a year and a half saying he's giving it "serious consideration." Fernando Guerra is a Political Science professor and Director of the Center for the Study of Los Angeles at Loyola Marymount University.