The detention of former Mexican President Carlos Salinas's elder brother Raul, charged with ordering and financing the murder of the secretary- general of the ruling Institutional Revolutionary Party (PRI), could be the last straw for the PRI's unbroken 65-year grip on power, many political analysts and intellectuals believe.
Tuesday's arrest of Raul Salinas, 48, a lifetime PRI member and one of Mexico's wealthiest and best-known businessmen, stunned a nation already reeling from political and economic crisis and an anti-PRI guerrilla uprising in the south. It also undoubtedly damaged Carlos Salinas's bid for the coveted leadership of the new World Trade Organisation (WTO), although the White House said yesterday it still backed him. It also threatened to embarrass President Bill Clinton over his recent support for a PRI government mistrusted and despised by an increasing number of Mexicans.
Raul Salinas was arrested for allegedly masterminding the assassination in September of Jose Francisco Ruiz Massieu in Mexico City. As secretary- general, Ruiz Massieu was the party's number two and a member of its reformist wing, those who believed it would have to open up to real democracy and end its Soviet-like control of all sectors of society in order to survive. Raul Salinas has long been identified with the PRI's hardliners, opposed to any change that would threaten their wealth and power base. Ruiz Massieu had also been married to a Salinas sister. They later divorced.
Announcing Mr Salinas's arrest, special prosecutor Pablo Chapa Bezanilla gave no motive, but investigators had previously said the assassination appeared to be a plot by the PRI's "dinosaurs", or old guard. Mr Chapa said Raul Salinas had been in "discreet but constant" contact with a PRI congressman, Manuel Munoz Rocha, missing since the murder and said by the prosecutor to have been the "joint mastermind" along with Raul Salinas.
The anti-reform motive inevitably led to comparisons with last year's other dramatic assassination in Mexico, that of Carlos Salinas's friend and hand-picked successor as PRI presidential candidate, Luis Donaldo Colosio, in the northern border city of Tijuana on 23 March. Days earlier, Colosio had given a keynote speech in which he suggested the days of the "dinosaurs" were over and that the PRI would have to democratise or face extinction.
The possibility of a direct link between the two killings emerged when the Attorney-General, Antonio Lozano, last weekend implied that Carlos Salinas's government had deliberately covered up the truth behind the Colosio killing to push the line of a lone mad gunman. Yesterday, three new witnesses emerged to say they also saw a second gunman fire on Colosio, identifying him as a local PRI militant in Tijuana who was detained last weekend. That appeared to back the Attorney-General's assertion of a well- organised plot to kill Colosio.
Raul Salinas's arrest raised the question: if he and the PRI old guard were prepared to get rid of Ruiz Massieu, who else but they would be the most likely suspects in the case of the reformist Colosio? What was Carlos Salinas's own stance and his relationship with his brother?
Carlos Salinas, at 46 two years younger than Raul, always billed himself as a moderniser and reformer. He was undoubtedly close to Colosio, who was his protg, and to Ruiz Massieu. But those who know him say his private persona was far tougher and much more hardline than the speeches for public consumption, aimed at braking the PRI's decline in its seventh consecutive decade in power. During his six-year term until last December, he appeared to be doing a balancing act between the reformers and hardliners, including his brother, who reportedly earned millions of dollars by getting the inside track on buying upprivatised enterprises.
There appears little doubt that Ernesto Zedillo, named PRI presidential candidate by Mr Salinas after Colosio's murder, has gambled on the unprecedented step of casting his predecessor to the wolves. But it is a huge gamble.
Some believe he may be seeking to deflect criticism of his three-month rule and boost his image as a reformer and law-enforcer.