In Mexico City's garish Cine Metropolitan, some thousand delegates of the official Party of the Mexican Revolution (P.R.M.) gathered in orderly array: blue-shirted, white-trousered campesinos (farm workers) on the right, professional men in the center, obreros (industrial workers) on the left. Eleven non-voting delegates from Los Angeles' big Mexican colony sat with them.
Outside, in the pleasant, leafy Paseo de la Reforma, clusters of public address horns rasped out the proceedings. Dark-suited politicos and tan-jacketed pistoleros (gunmen) listened intently while the party changed its name to Institutional Revolutionary Party (P.R.I.). The...