A few hours before the deadline for ending the campaign for Sunday's presidential and parliamentary elections, the populist candidate of the Party of the Democratic Revolution (PRD) suggested that only he could reach an accord with Marcos's Zapatista National Liberation Army (EZLN).
For the first time in his campaign, he appeared to call on the Mexican armed forces to support 'democratic transformation' in the event of electoral fraud. Since cries of fraud are almost inevitable if the ruling Institutional Revolutionary Party (PRI) wins, Mr Cardenas was challenging Mexico's traditionally pro-PRI generals to stand up and be counted.
'I trust the armed forces will be attentive and vigilant to ensure that constitutional rights are not violated,' he said in Tapachula, on Mexico's southern border with Guatemala.
A crowd of more than 25,000 people, some of them perched precariously on flat-topped laurel trees in the main square, listened. 'The armed forces have the obligation to guarantee that constitutional order will prevail,' he added. 'I trust that the members of the army, navy and air force will know how to fulfil this responsibility and will constitute a fundamental pillar of our democratic transformation.'
He spoke without notes but his language was studied. Mr Cardenas, running third in questionable opinion polls, behind the PRI and the conservative National Action Party (PAN), was calling on the military to distance itself from the party that has won Mexico's presidential elections by foul means or fair for six-and-a-half decades.
The generals have been a pillar of the one-party system. But they are known to have been frustrated by President Carlos Salinas's orders not to crush the Zapatista guerrillas earlier this year.
Suggesting he will not accept defeat from the PRI candidate, Ernesto Zedillo, or from PAN's Diego Fernandez de Cevallos, Mr Cardenas appealed to his supporters. 'I invite you all to be here in this square, at noon on 22 August, (the day after the elections) and all Mexicans to be in their main squares in towns and villages around the country at the same time to celebrate our victory.'
Since his outright victory seems unlikely, he appeared to be hinting about initiating what he and the guerrilla leader, Marcos, have called 'civil resistance', in the event of electoral fraud. Mr Cardenas was making a gamble in closing his campaign in Chiapas. The PRI won the 1988 presidential elections in this state with almost 90 per cent of the vote. That was a reflection more of coercion than popularity.
Before his final speech in Tapachula, Mr Cardenas drove into the mist-shrouded mountains of Chiapas's Sierra Madre to the small town of Motozintla, a long- time PRI stronghold. Only some 1,000 people, mostly local Tzotzil or Mame Indians, ventured to the tiny square to support Mr Cardenas. Most were lost for words when he sang the national anthem. Few responded when a former cinema sex symbol, Irma Serrano, running for senator for the PRD in Chiapas, yelled 'Viva Marcos' in reference to the guerrilla chief.
A local doctor, Jorge Flores, 39, attending the Cardenas rally, was one of the few people who dared answer my question. 'People here are afraid,' he said. 'One of the major problems is the influx of outside religions. Around half of the 48,000 people in this municipality have converted. There are Mormons, Adventists, Jehova's Witnesses, Evangelicals, Pentecostalists. The authorities tell them 'if you don't vote for the PRI, we'll close down your church.' The same goes for state employees.'
'The PRI brings people across the border from Guatemala and gives them fake voting credentials,' an Indian woman said. As almost everyone remained silent when I questioned them, why was she not afraid?
'We all have to die sometime. We are not eternal on this earth. The problem is our children. We never know what might happen to them,' she said.
The PRD's candidate for governor of Chiapas, a lawyer and journalist, Amado Avendano, closed his campaign in San Cristobal de las Casas. He was appearing in public for the first time since what he called an 'assassin lorry' hit his car, injuring him and killing three PRD campaigners last month. Mr Avendano was unable to talk. His daughter read his closing speech for the only state governorship at stake on Sunday.
Mexico's Human Rights Commission said yesterday its investigations had suggested an accident. Mr Avendano and his family believe opponents tried to kill him.