A Colombian soldier stands guard near the site where Revolutionary Armed Forces of Colombia (FARC) guerrillas killed 13 soldiers in an attack shortly after officials announced talks with the leftist rebels would resume, Aug. 25, 3013. (DANIEL MARTINEZ/AFP/Getty Images)

Colombia’s constitutional court will rule as early as Wednesday whether a government plan to address war crimes through its peace process with Marxist guerrillas is constitutional, a decision that could determine the outcome of President Juan Manuel Santos’s efforts to end a half-century of conflict here.

Many Colombians are concerned that a ruling in the government’s favor would allow the FARC rebel group’s commanders to walk away unpunished once peace is negotiated. The conflict, in which the United States has provided $9 billion in mostly military aid since 2000 to help weaken the rebels, has cost the lives of tens of thousands of civilians.

According to a study by the state-supported National Center for Historic Memory, the FARC, or Revolutionary Armed Forces of Colombia, has killed villagers, launched hundreds of attacks on small towns and, from 1970 to 2010, kidnapped nearly 13,000 people, including Americans.

Among those following the proceedings with misgivings are German Bernal and his family — his parents and uncles and aunts from the mountainous state of Tolima. They lost their farm in 2000 when rebels forced them off. The rebels destroyed the small, private school that Bernal’s mother, Myrian Ordoñez, ran. And an uncle, Reynel Bernal, was killed by the guerrillas. “I think the government, in its rush to find peace, is doing things we don’t agree with on the issue of justice,” said German Bernal, 35, who represents victims of the conflict in Tolima.

The government’s Legal Framework for Peace, a constitutional measure creating a mechanism for delivering justice as the country transitions from war, has become a political thicket for the president and his peace negotiators.

Government officials know FARC commanders will continue their bloody fight, with its attacks on civilians as well as soldiers, if justice for the victims of war includes jail time for the rebels. In delivering the holy grail of peace to Colombia, the government also needs to satisfy a Colombian public that scorns the FARC while meeting human rights treaty obligations requiring that perpetrators of war crimes receive punishment proportionate to their crimes.

“It’s the search for the right balance between peace and justice,” said Sibylla Brodzinsky, co-editor of “Throwing Stones at the Moon,” a recently published book on victims uprooted from their homes by Colombia’s conflict. “What it comes down to is if you demand too much justice, then peace is at risk. If you prioritize peace over the demands of justice, you could be creating the basis for an entirely new conflict.”

The government is adamant that the framework for justice, the details of which Congress would develop, does not mean amnesty or impunity. Officials say justice would be delivered through investigations of systematic rebel crimes, atrocities deemed emblematic of a brutal conflict. The findings could then be made public through a special “truth commission” or in a report, though none of that has been decided.

Sergio Jaramillo, the government’s peace commissioner, said the central idea is to uncover the truth about what happened and determine responsibility.

Investigating every atrocity, officials argue, would amount to a de facto impunity because there is no way an overburdened judiciary would be able to clear up the countless crimes. Jaramillo argued before the court that by concentrating investigations on “those who are most responsible for international crimes, the better we will understand who were the sponsors” of atrocities.

But critics say that means many of the rank-and-file rebel fighters who committed crimes will not be judged, because the government plan calls for a focus on “the maximum ones responsible.” And the government and FARC commanders are this week negotiating the participation of rebels in politics once hostilities end, a point that is dividing Colombian society.

None of it sits well with Yolanda Gonzalez, 44, whose brother, Ruben Gonzalez, was shot to death by the FARC in 2002. The rebels also forced her off her farm, and she and her five children had to spend two years living under a tarp in a camp for farmers displaced by the conflict.

“So many years pushing people off their farms, killing people, and now the government gives them participation in politics?” she asked, incredulous. “I think not. They should pay for what they did.”

The chief prosecutor for the International Criminal Court in the Hague recently wrote two pointed letters to the constitutional court here expressing concern that the government’s mechanisms for delivering justice could “invalidate” the peace process.

Fatou Bensouda of Gambia wrote that the suspended sentences the Colombian framework could permit suggest that the objective is to “shield the accused from responsibility.”

Among those who presented an amicus brief to the court against the framework was JoséMiguel Vivanco, the Americas director of Human Rights Watch, who said that “Colombia clearly needs to offer some kind of legal benefits to the FARC.” But Vivanco said that “there are certain non-negotiable limits on how much Colombia can concede in the name of peace.”

The government, though, says the framework must be seen in broader terms — that it is part of a peace deal that, if successful, would mean lives saved and a more robust economy that would improve living standards. The end of hostilities, in which the FARC guerrillas would voluntarily submit themselves to being investigated, would shine a light on crimes that were committed.

“The conflict has not yet ended,” Santos said recently, “and it’s with the end of the conflict that will come the hour of truth.”