I am not much of an admirer of Julián Castro’s, but it is remarkable to me that a Latino man who was mayor of a major American city (at 1.5 million residents, San Antonio is Texas’s second-largest city) was of so little interest to Democrats, while Pete Buttigieg, the Anglo former mayor of a city that might very generously be described as “minor” (South Bend, Ind., is less than a third the size of Henderson, Nev.) is on the rise. Pete Buttigieg of South Bend, Elizabeth Warren of Cambridge, Mass., and Bernie Sanders of Burlington, Vt. — white people from college towns apparently are the heart and soul of the Democratic party. Such as it is.