Andrés Manuel López Obrador’s latest address to thousands of supporters in the Zócalo, Mexico City’s main square, was a scene Mexicans have grown used to since the leftwing leader lost out to Felipe Calderón in the country’s closest election.
But beyond his criticism of the country’s electoral authorities, his constant snipes at Vicente Fox, the outgoing president, and his insistence that the July 2 vote was fraudulent, the thrust of the leftwing candidate’s speech contained a notable change of tone.
“Never again will we allow them to install an illegal and illegitimate government in our country,” he told a baying crowd. “Here and now begins a new period in Mexico...with the sovereign power of the people we will undertake the changes and transformations that this country needs.”
For Jorge Zepeda, a political analyst in Mexico City, the speech signaled the start of a more radical phase in Mr López Obrador’s campaign to revert the result of last month’s election.
For the first time since election day, for example, Mr López Obrador concentrated less on claims of election fraud and more on what he would do once Mr Calderón, candidate for Mr Fox’s National Action Party (PAN) was named president-elect.
These included mounting protests at every one of Mr Calderón’s public acts, and holding another rally in the Zócalo on September 16 - the same day that Mexico’s armed forces traditionally parade in the square to mark the country’s independence. He also said his blockade of Paseo de la Reforma, a central avenue in Mexico City, could last for years.
“He’s now talking about a more permanent phase of opposition, and one in which the discourse has become far more radical,” says Mr Zepeda. “It’s very worrying.”
Political commentators such as Mr Zepeda argue that this new tack of Mr López Obrador’s so-called “pacific civil resistance” movement poses risks for the leftwing candidate.
For example, some prominent academics and intellectuals have openly criticised Mr López Obrador’s decision to blockade Paseo de la Reforma, and have begun to distance themselves from a movement that just weeks ago they endorsed.
At the same time, Mr López Obrador’s supporters appear to have become more extreme. Some followers of Sub-commander Marcos, the masked guerrilla leader who led a 1994 uprising in Mexico’s poverty-stricken southern state of Chiapas, have joined the movement they publicly rejected several months ago.
Another clear danger is that a more radical resistance strategy could alienate many members of Mr López Obrador’s party. Leaving aside Mr López Obrador’s defeat by Mr Calderón, the party won many seats in the federal Congress, and has now become the second most important force in Mexican politics.
“Sooner or later all this is going to produce a serious conflict of interests because many PRD members want a party, not a social movement,” says Mr Valdés.
So why is Mr López Obrador risking so much?
One reason, argues Mr Valdés, is that Mr López Obrador, who enjoys string support in Mexico City, is convinced his political platform is morally superior to that of his adversaries. “López Obrador sees this as a political fight between good and bad,” he says. “It is not an electoral fight any more.”
But Manuel Camacho, one of Mr López Obrador’s key strategists, says the struggle remains centred on tangible facts of fraud. The latest proof of that, he argues, is the long list of “irregularities” that have surfaced from a partial recount of the votes ordered last week by Mexico’s electoral tribunal.
He says the partial recount has already shown that a huge number of ballot boxes contained more votes than there were people on the corresponding electoral register. “If the tribunal annulled those ballot boxes – a step they are obliged to take legally – Andres Manuel would win the election by almost 29,000 votes,” he says.
Unsurprisingly, perhaps, members of Mr Calderón’s PAN party do not agree.
Mr Valdés says Mr López Obrador’s increasingly beligerent stance could create a violent confrontation with Mr Fox’s administration.
For days, Mr Fox guarded an uncharacteristic silence over Mr López Obrador’s actions and comments. But his self control appears to have weakened; on Monday he vowed to ensure that the next president would take up his position on December 1 come what may.
The same day, federal police clashed with PRD supporters outside the lower house of Congress. Twenty people were injured, 15 of whom were PRD members of congress.
What happens next could depend on how members of Mr López Obrador’s party react to the tribunal’s final ruling on the election – it must proclaim a president-elect by September 6.
Until then, Mr López Obrador appears intent on playing a dangerous game of chicken with the rest of Mexico’s political leaders. “He is speeding at full throttle towards the cliff to see who take his foot off the accelerator first,” says Mr Valdés.