By Uki Goñi - Political “suicides” are so common in Argentina that a special word has been invented for them. Ask different people in Buenos Aires today and they may disagree whether the crusading prosecutor Alberto Nisman was murdered or took his own life. But most everyone will concur that Mr. Nisman was “suicided,” the latest victim of a dark-power centrifuge that with sinister regularity spews out dead bodies in this divided nation.