For seven decades, the Institutional Revolutionary Party ruled Mexico by hook or by crook, stuffing ballot boxes, massacring democracy protesters and bribing journalists into providing sycophantic coverage. When it finally lost a presidential election for the first time, in 2000, the atmosphere was reminiscent of the fall of the Berlin wall.
But now the party, universally known in Mexico as PRI, its Spanish initials, is on the brink of a triumphant comeback, with its youthful candidate for July's presidential polls, Enrique Peña Nieto, enjoying a consistent lead of around 20 points over his nearest challenger.
In the race for congress, the PRI, buoyed by its alliance with Mexico's controversial, death penalty-supporting Green party, is close to winning 50 per cent of the lower house. That would be the chamber's first outright majority in some 15 years, giving Mr Peña Nieto, a 45-year-old former governor of the massive state of Mexico, which includes much of Mexico City, more power than any president has had since the early 1990s.
That prospect has triggered a wave of protests across the country as many Mexicans recoil at the return of a political machine that ransacked the public purse and ruthlessly sidelined challengers to its power during 71 uninterrupted years in power. Occasionally that involved killing opponents, such as in the notorious Tlatelolco massacre of democracy protesters threatening to disrupt the 1968 Olympics. But more often than not, it saw the PRI cleverly co-opt its most trenchant critics, even offering juicy ambassadorial posts around the world.
Anti-PRI protests reached a peak last month when Mr Peña Nieto visited Mexico City's private Iberoamericana university. Angry students waved banners blaming the PRI for a long list of Mexico's ills. Perhaps the most cutting message, referring to the party's time in power, simply read: "We remember."
Mr Peña Nieto, who has an MBA but has spent his entire career as a PRI activist, has repeatedly insisted that the party has changed, and that his election will not signal a return to the dark ways of the past. "In the Mexico that we desire, there will be no room for corruption or cover-ups and much less impunity," he said recently. "It's time to break with the past."
Yet many doubt his ability to lead a complex nation of 112 million people, wracked by the drugs war and with an economy that, despite being the world's 12th largest, sees one in five Mexicans without enough to eat. This impression has only been heightened by the candidate's matinee idol good looks, his marriage to a telenovela starlet and his inability last year to name three books that had influenced him.
Some of the most withering criticism has come from the writer Carlos Fuentes, who died in May. He famously described Mr Peña Nieto as having "scarce intellectual resources" and being too ignorant to be President. "The problems demand a man who can converse on equal terms with Obama, Angela Merkel or Sarkozy, and he [Mr Peña Nieto] is not capable of doing that," Fuentes told the BBC's Spanish-language service.
Meanwhile, the fact that many of Mr Peña Nieto's inner circle previously worked for President Carlos Salinas – whose 1988-1994 administration marked a nadir for Mexico in corruption and political Machiavellianism – has led to accusations that the candidate is no more than a puppet of Mr Salinas.
Mr Salinas is remembered for breaking with the PRI's leftist past, born of the Mexican revolution, to push a massive programme of privatizations and deregulation along with a trade treaty with the US and Canada, as the Mexican economy opened up to the outside world.
Unfortunately, his term also ended in the Tequila crisis, as the Peso collapsed while indigenous Zapatista rebels, claiming to have been abandoned and abused by the government, rose up in Mexico's southern jungles. Mr Salinas ended up spending years in exile in Ireland, apparently fearing a high-profile trial.
Mr Peña Nieto also appears to be reviving some of the PRI's old autocratic habits, such as paying for media coverage. Local papers revealed that as Mexico state governor, he paid out 32 million Pesos (£1.5m) to journalists. Roughly a third went to two TV anchors, one of whom, Joaquí* López Dóriga, fronts the flagship news show of private broadcast giant Televisa, which dominates national ratings. Unsurprisingly, protesters have staged a series of marches at what they regard as heavy media bias in favour of the PRI. Nevertheless, many of Mexico's young, rapidly-growing population have no memories of PRI's time in power.
And after six years of a drug war, declared by President Felipe Calderón, of the conservative National Action Party or PAN, that has cost some 50,000 lives, many crave the stability and relative security once provided by the PRI. The violence has helped dump the PAN's presidential candidate, Josefina Vázquez Mota, into third place, with 24 per cent. Last month, she finally caved into pressure to distance herself from President Calderón's hardline stance against the drug traffickers – and the related human rights abuses frequently committed by the police and armed forces.
She now trails Andrés Manuel López Obrador, the candidate of the leftwing Democratic Revolution Party, or PRD, who is in second place with 27 per cent, according to polls. The former Mexico City mayor led nationwide protests in 2006, alleging fraud, after narrowly losing to Mr Calderó* in that year's presidential contest. He subsequently apologised and, after years of trying to shake his reputation as one of Latin America's dinosaur left, he is rising in the polls. But the scale of Mr Peña Nieto's lead – he is on 45 per cent – would require nothing short of a political earthquake for Mr López Obrador to overhaul him.
The presidency: runners and riders
Enrique Peña Nieto
Suave and telegenic, the new face of the PRI is leading in the opinion polls with 45 per cent of the vote.
Andrés Manuel López Obrador
First came to prominence in early 1990s during a power struggle with a PRI chieftain in Tabasco state. Now the PRD candidate, he is in second place with 27 per cent.
Josefina Vázquez Mota
Former economic journalist, Mota is the first female presidential candidate for a major party – the ruling PAN – in Mexico. Third with 24 per cent.
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