Mexico
Authoritarianism Unveiled, 1964-70
... As the Olympic Games approached, the PRI and Díaz Ordaz were preparing the country to show foreign visitors that Mexico was politically stable and economically sound. Student unrest grew louder and more violent, however. Student demands included freedom for all political prisoners, dismissal of the police chief, disbanding of the antiriot police, guarantees of university autonomy, and the repeal of the "law of social dissolution" (regulating the punishment of acts of subversion, treason, and disorder). Luis Echeverría Álvarez, the new interior minister, agreed to discuss the issues with the students but changed his mind when they demanded that the meeting be televised. The students, their demands unmet, escalated the scale and frequency of their protests. In late August, they convened the largest antigovernment demonstration to date, rallying an estimated 500,000 protesters in the main plaza of the capital. Seeking to bring a halt to the demonstrations, Díaz Ordaz ordered the army to take control of UNAM and to arrest the student movement leaders.
To show that they had not been silenced, the students called for another rally at the Plaza of the Three Cultures in Mexico City's Tlatelolco district. On October 2, 1968, a crowd of about 5,000 convened on the plaza in defiance of the government crackdown. Armed military units and tanks arrived on the scene and surrounded the demonstrators, while military helicopters hovered menacingly overhead. The helicopters began to agitate the crowd by dropping flares into the densely packed gathering. Shortly thereafter, shots rang out (according to some accounts, the shooting was started by the military, while others claim the first shots were fired at soldiers by antigovernment snipers in the surrounding buildings). The panicked crowd suddenly surged toward the military cordon, which reacted by shooting and bayoneting indiscriminately into the crowd. Estimates of the number of people killed ranged from several dozen to more than 400. Despite the violence, the Olympic Games proceeded on schedule. However, the Tlatelolco massacre had a profound and lasting negative effect on the PRI's public image. The authoritarian aspects of the political system had been starkly brought to the surface ...
http://www.country-data.com/cgi-bin/query/r-8712.htmlBut the PRI stranglehold was loosened a few years back. Mexico's having local elections, too, aren't they? But what difference could it make in locales where the PRI isn't a real contender?