IN Mexico, there is a word for politicians who dominate regions through arbitrary power and family connections: cacique. This week, Mexico's most notorious cacique toppled, sending tremors through a political system that critics say has merely paid lip service to the rule of law.
Ruben Figueroa Alcocer, governor of the Pacific coast state of Guerrero, resigned Tuesday in the face of international condemnation of his regime for the massacre last June of 17 unarmed peasants by state police.
The massacre had become a major embarrassment for President Ernesto Zedillo Ponce de Leon. The Mexican president has vowed repeatedly to reform police and wipe out official impunity. At the same time, he has sought to avoid alienating powerful hard-line leaders, like Mr. Figueroa, within his own ruling Institutional Revolutionary Party, or PRI.
Nonetheless, PRI president Santiago Onate has moved to distance the party from the fallen governor - and to send a message to others like him.
''Our party does not offer unconditional support, nor blank checks,'' Mr. Onate told correspondents here Tuesday. ''We will only back those party members in public office who conduct themselves according to the law.''
In Guerrero, the PRI-dominated legislature named a Figueroa ally as interim governor. Angel Aguirre Rivero, who previously served as a federal legislator and state party president, has vowed to cooperate with the investigation and shake up his Cabinet.
Cracking down on political impunity poses problems for President Zedillo. On the one hand, he is committed to decentralizing the authoritarian regime of the PRI that has ruled Mexico for 67 years. On the other, pulling the presidency out of regional affairs means that some local rulers could run amok.
''Local political leadership can have an ugly face,'' said Soledad Loaeza, a political scientist here at the Colegio de Mexico. ''The case of Guerrero shows us the urgency of developing new rules, and new institutions, so that there is not a power vacuum. We must have institutions prepared to effect change.''
Prodded by outcries from human rights groups and opposition parties, Zedillo last week ordered the Mexican Supreme Court to reopen the investigation into the massacre after a special prosecutor in Guerrero had cleared Figueroa and several top lieutenants of wrongdoing.
To date, more than 50 Guerrero public-safety agents and mid-level officials have been charged for crimes ranging from homicide to dereliction of public duty.
Last year, a national human-rights commission accused Figueroa's government of a coverup. Figueroa at first claimed that the peasants provoked the confrontation on June 28, 1995, which occurred at a purported checkpoint for illegal arms near the rural village of Aguas Blancas. But a videotape of the scene, recently reconstructed and aired by the Mexican network Televisa, showed otherwise.
In a farewell letter, Figueroa stoutly denied any blame.
Leaders of the center-left Party of the Democratic Revolution, or PRD, were jubilant. Several of the peasants killed in the massacre were apparently bound for a leftist protest rally. The PRD, which led a relentless nationwide fight to oust Figueroa, claims that more than 80 of its sympathizers were killed in Guerrero during the governor's term, allegedly for political motives.
''They're shouting for joy here,'' says Carlos Payan, a PRD official in Guerrero. ''We're satisfied and proud for the people of Guerrero. Figueroa fell because he was a poor governor. He faced one problem after another, one massacre after another.''