Calderon deemed that “with strong blows he could do the enemy in, and it didn’t work out. And we know that the army violates human rights every day but no one says anything,” Fox told Madrid’s newspaper El Pais last week during a visit to Spain.

He said Calderon was finishing his term with only 20,000 more inmates in jail than were there when Fox’s term ended.

“And for this we have 70,000 deaths? What was this war good for?” he asked.

The crime panorama in Mexico has changed dramatically in the past half decade, as drug gangs fought each other for turf and smuggling corridors. Where once there were six or seven powerful narcotics groups, there’s now just one dominant one, the Sinaloa Cartel.

Numerous other groups are less powerful. In the past three months, the Mexican navy – backed by U.S. intelligence – has dealt severe blows to the once-dominant Los Zetas and the smaller Gulf Cartel.

Homicide rates have fallen this year, and beheadings and massacres – once weekly occurrences – are far less frequent. Of the 37 most wanted drug and crime lords identified when Calderon took office, he says 25 have been “neutralized”: They’re dead or behind bars.

Where Mexico has failed on Calderon’s watch, though, is in arresting criminal suspects, carrying out successful prosecutions and keeping them in jail, experts said. Calderon deployed soldiers and federal police without having his government codify rules for the use of force or enforcing strict accountability for abuses.

“By ordering intensive confrontation with organized crime, he sparked an enormous human rights crisis,” Lopez Portillo said. “Accusations of torture (by state agents) grew fourfold in the last six years.”

Charges of routine use of torture by the armed forces and federal police have been documented or reflected in reports by Human Rights Watch, Amnesty International, various U.N. groups and the U.S. State Department.

“If these are investigated, obviously responsible parties would be found,” Lopez Portillo said.

Some will seek to lay ultimate legal responsibility on Calderon.

One of Calderon’s predecessors in power, Ernesto Zedillo, who governed from 1994 to 2000, faced a civil lawsuit in U.S. federal court blaming him for crimes against humanity for a 1997 massacre in Guerrero state. The U.S. government told the court in September that Zedillo should be granted immunity, meaning the suit is likely to be quashed.

Concerned about his own potential legal travails, Calderon has worked closely with Pena Nieto in the transition period, leading to speculation that the two reached a tacit accord over Calderon’s future should judicial trouble arise.

“Experience tells me that the legal future of President Calderon depends fundamentally on two political factors: Pena Nieto and the United States,” Lopez Portillo said. “If the United States decides to exert pressure so that Calderon is not charged, he will not be charged.”