Updated

After negotiating the demobilization of the M-19 rebel movement he co-led, Antonio Navarro helped draft Colombia's 1991 constitution, ran for president and became a big-city mayor and a state governor. And he did it all bearing the scars of war: a wooden leg and slurred speech from a grenade attack.

If anyone understands the bitter costs and frustrating political complexities of Colombia's half-century-old conflict, it is Navarro. That's why, he says, he is backing President Juan Manuel Santos' "Peace Framework" law, a constitutional amendment that sets a roadmap for government negotiations with leftist rebels.

"We have an obsolete war," Navarro, 64, says of the Western Hemisphere's last remaining ideology-rooted armed conflict, tapping on the wooden leg he has worn since surviving a 1985 assassination attempt, which also cost him control of his tongue. "Is it really necessary to keep producing new victims?"

But the law passed last month by lawmakers is meeting fierce resistance from two camps that normally share little affinity: Colombia's right wing, led by former President Alvaro Uribe, and human rights activists. Their issue is the general amnesty that lies at the center of the law.

Uribe, who is credited with badly weakening Revolutionary Armed Forces of Colombia, or FARC, guerrillas with U.S. military assistance during his 2002-2010 government, complains that the law will let rebel leaders off scot-free and make murderers eligible for public office.

"It will allow those responsible for terrible crimes to go uninvestigated," Uribe said in a seven-point written critique expressing his concern that rebel leaders who have committed high crimes will be eligible for political office.

The Americas director of U.S.-based Human Rights Watch, Jose Miguel Vivanco, who rarely sees eye to eye with Uribe, sides with him on the amnesty, which would also apply to security force members.

"What's most serious about the text is that it offers those most responsible for crimes against humanity the benefit of not serving a single day in prison," he said.

But no rebel leader will sit down at the negotiating table without the understanding that they won't face prison, says the 64-year-old Navarro in his Bogota apartment. Conflicts have been settled with such amnesties throughout the country's bloody history, he said.

No official government death toll exists for Colombia's internal conflict, but political analyst Ariel Avila of the Nuevo Arco Iris think tank ventures a calculation of about 240,000 deaths from 1985-2005. The war amounted to a slow bleeding in which hit-and-run rebel attacks on security forces were met with a dirty war of massacres, assassinations and forced disappearances in which right-wing death squads, often military-backed, played a major role.

Pro-government legislators say the new law doesn't cover civilians nor members of the armed forces who committed crimes outside the conflict such as extrajudicial executions, espionage or corruption. If the interpretation holds, that would mean drug traffickers, far-right militias and death-squad members could still be prosecuted.

Among the FARC actions deemed criminal by Colombian courts is the 2003 bombing of the exclusive El Nogal social club in Bogota that killed 36 people. Hundreds of civilians have also been kidnapped.

Santos has pointed out that the law only sets general guidelines for a peace process that hasn't begun, not even in a preliminary stage. In fact, the FARC has been stepping up attacks on security forces and oil installations in recent months, even after announcing in February that it was halting ransom kidnappings.

In the immediate term, the law faces a roadblock in the country's constitution, which only allows amnesty for political crimes, not war crimes, said Carlos Gaviria, a former Constitutional Court judge.

To get around that, the framework law specifies that legislators later define the parameters of crimes against humanity, genocide or war crimes and then allow suspended sentences.

Vivanco called the work-around "a farce" that will still let off killers. He said the International Criminal Court could ignore the amnesties, claim jurisdiction and begin prosecutions.

The framework law's author, congressman Roy Barreras, says such criticisms ignore its intent and scope. The point is to give the president the means to negotiate peace, not to give him unlimited powers to achieve it.

"We are not giving the president a blank check, and certainly not to armed groups," said Barreras.

Supporters of the peace framework say the amnesty is an essential concession to FARC leaders, who have been seeking a peace dialogue with Santos since he took office in August 2010. The guerrillas' most recent negotiations with a Colombian government ended in disarray in 2002, when they continued to attack government forces and kidnap politicians even after being granted them a safe haven in the country's south for more than three years.

A Colombian who knows the FARC's leadership well, Communist Party weekly La Voz editor Carlos Lozano, says that neither the FARC nor the country's far smaller No. 2 rebel band, the National Liberation Army, would seriously consider any peace offer that didn't exempt their leaders from prosecution. Timochenko, the nom de guerre of 53-year-old Rodrigo Londono, and others on the FARC's ruling seven-member secretariat will also likely object to the law's requirements that they disarm and dismantle their forces, Lozano said.

"To think that Timochenko would agree to become a prisoner with no political rights: They'll never accept that," Lozano said.

In a late June statement, the FARC was cool to the law, calling it "cynical" and saying Santos is only interested in "a repentant, weepy guerrilla force that surrenders on its knees."

FARC leaders, in previous peace negotiations, have been loath to disarm, saying they fear becoming targets of political assassination. They speak from experience: Some 4,000 of them disarmed and entered politics in the 1980s as members of the Patriotic Union party only to be systematically killed by right-wing death squads.

One model Colombians have studied is how El Salvador arrived in 1992 at an end to a 12-year-old conflict that claimed more than 75,000 lives.

Peace talks there led to legal guarantees for ex-combatants on both sides, including a general amnesty decreed by then-President Alfredo Cristiani.

The Rev. Gregorio Rosa Chavez, who took part in peace talks with rebels as San Salvador's deputy Roman Catholic Bishop, said Cristiani "asked everyone to look ahead and forget the past. What did the church say? That before we look ahead, before we turn the page, we need to read it. You just can't lay aside truth and justice."

Yet El Salvador largely did.

No one was ever sanctioned for the security force massacre of 936 civilians in 1981 in the Salvadoran village of El Mozote, or the 1980 murder of Archbishop Arnulfo Romero.

Rosa Chavez, however, sees Colombia's conflict as more complicated, its guerrillas less idealistic, with drug trafficking obscuring the FARC's stated political goals of agricultural reform and a more equal distribution of wealth.

The challenge is to strike "a complicated balance" that honors international humanitarian law while being realistic enough to promote reconciliation, said Antonio Sanguino, a Bogota councilman with the Green Party.

Sanguino had belonged to a small rebel group called the Socialist Renovation Current that made peace with the government in 1994. Now, he says the time has come for all parties to end the conflict.

"In the name of justice we can't deny Colombian society the right to peace," he said. "And in the name of peace we can't ignore the rights of the victims."

___

Associated Press writer Frank Bajak contributed to this report.