Weary Mexicans ready to reject the old system: The country's rulers appear in danger of being overtaken by events beyond their control

TO Mexicans, the phrase 'the system has collapsed' is as much a catchphrase as 'the pound in your pocket' or 'the green shoots of recovery' to Britons.

On election night 1988, the then interior minister, Manuel Bartlett, was referring to the government-run computer system which 'collapsed' just as populist presidential candidate Cuauhtemoc Cardenas looked set to defeat Carlos Salinas de Gortari and end six decades of rule by the Institutional Revolutionary Party (PRI). PRI officials now admit privately that the 'collapse' was a trick and that Mr Cardenas would have won.

Six years on, the same catchphrase is taking on new meaning. Barring miracles, black magic or the mother of all frauds, it is the Mexican system itself - the PRI and the institutions it controls - which appears on the point of terminal collapse.

Next Sunday's six-yearly presidential elections are billed as the closest and the cleanest in Mexico's history. This may be true but the result could prove irrelevant when events are changing faster than anyone could have imagined a year ago. The presumably-close election result may simply be the beginning of a transition to democracy in a country that has long been something of a Soviet-style state minus the ideology.

Closing his campaign before more than 100,000 supporters in Mexico City's zocalo (main square) on Saturday, Mr Cardenas, presidential candidate of the left-wing Democratic Revolution Party (PRD), suggested he would not accept defeat again. Nor did he leave any doubt that he and his party had now linked their fate to that of the so-called Zapatista guerrillas of the south-eastern state of Chiapas.

'If there is fraud, I pledge to call and head the civil resistance,' Mr Cardenas said. 'No one, nothing will contain the anger of the people, no one will be able to oppose the immediate civil resistance.' He was clearly referring to the civil resistance mentioned by subcomandante Marcos of the Zapatista guerrillas at a jungle convention last week. Mr Cardenas's platform backdrop carried the white dove symbol of Marcos's jungle convention, and Rosario Ibarra, the fiery left-wing activist appointed in the Lacandon jungle to head the broadened civilian leadership of the Zapatista guerrillas, spoke at the rally.

Although there had been little doubt Mr Cardenas's party's platform largely coincided with that of Marcos's Zapatista National Liberation Army (EZLN), it was the first suggestion of collusion.

Mr Cardenas called on his supporters to take to the streets - 'totally in accordance with the law' - on 22 August, the day after the elections, 'to celebrate our victory'. In effect, since even his closest advisers doubt he could win outright, he appeared to be invoking 'civil resistance' to what is most likely to be a narrow and probably untenable PRI victory.

Mr Cardenas appeared to be assuming responsibility over a broadened opposition movement including the Zapatista guerrillas. They had said last week they were putting themselves under the command of their National Democratic Convention to be headed by Mrs Ibarra.

Despite Mr Cardenas's constant references to staying within 'peace and the law,' he appeared to be warning the PRI and the government that he had influence over whether the EZLN return to arms.

There are no ideological issues in this election. It has simply come down to a battle over whether the results should be believed. The PRI has concentrated its efforts not on policy but on the assurance that the elections will be clean. Much has been made of the fact that the UN is supervising the elections - not as observers, which would upset Mexico's idea of sovereignty, but as 'visitors' - and that Mexican volunteer 'vigilantes' will be watching polling booths. In fact, the Federal Electoral Institute, though multi- party, will be headed by the Interior Minister, Jorge Carpizo, a close friend of Mr Salinas.

Opinion polls almost unanimously suggest the PRI will win. Not, as in the old days, with the 90-odd per cent they used to enjoy - like Khomeini or Gaddafi using similar means. The 'polls' suggest the PRI presidential candidate, Ernesto Zedillo, will win with something like one-third of votes cast. Were you to believe the polls, the conservative National Action Party (PAN) candidate, Diego Fernandez de Cevallos, would come second and Mr Cardenas a distant third.

The polls, however, bear little resemblance to what journalists have ascertained on city streets and in the countryside. One poll, by the Voz y Voto (Voice and Vote) magazine even published an 'Analysis of those how did not respond'. Only a higher power must know how, but they assured reporters most of those who did not respond would vote for the PRI.

'The polls here simply do not tell the truth,' said Jorge Castaneda, one of Mexico's leading intellectuals who is part of a group trying to avoid violence during and after next week's poll. 'One: people don't tell the truth. There's a tradition of fear. Two: the polls are biased,' he said.

Mr Castaneda said he believed subcomandante Marcos was 'going through the motions, to give peace a chance, so to speak,' but that the EZLN remained ready to fight and that there were probably armed movements beyond the state of Chiapas. Another leading intellectual, writer and historian, Enrique Krauze, appeared to agree. 'Civil war is not out of the question,' he said in an interview.