MEXICO CITY — Legendary Colombian cocaine king Pablo Escobar is as dead as Pancho Villa. But the way he and other capos unleashed terror, before the government killed them years ago, offers lessons for both forces as Mexican President Vicente Fox vows to wage the "mother of all wars" against this nation's drug cartels. If the cartels feel greatly threatened, they could strike harder at civilians, police and government institutions, and upgrade from guns to bombs. But if the mafias get too bold, the government could unleash all its power, and cartels seldom are a match for armies. It's a...