BOGOTA - Colombia said Wednesday it was ready to start negotiating with its second-largest rebel army, potentially broadening a peace process aimed at ending Latin America’s oldest insurgency.

The country’s Constitutional Court provided more enticement for rebels to stop fighting and end nearly 50 years of bloodshed, ruling that fighters who lay down arms can take part in politics after a peace process is completed. The ruling endorsed a constitutional amendment that lawmakers approved in 2012. The conflict in Colombia goes back to the 1960s and has its roots in gaping inequality between wealthy landowners and landless peasants. It is a volatile and violent mix that has also drawn in other leftist rebel groups, rightwing paramilitaries and drug traffickers. An estimated 600,000 people have died, and another 4.5 million are displaced within the country because of the violence.

“This is an extremely important step in the desire that all Colombians have, which is a country at peace,” said President Juan Manuel Santos, alluding to the court ruling.

But another rebel group already negotiating with the government balked, saying the reform was unilateral and did not include their input. The rejection came from FARC leader Ivan Marquez. The FARC is the largest rebel army.

In a statement, Santos hailed the National Liberation Army’s release this week of a Canadian hostage and said “the government is ready to start a dialogue with the ELN as soon as possible.”

He had made talks with the rebels, known in Spanish as the ELN, contingent on the release of captives.

The ELN announced Tuesday that it would release the 47-year-old, who works for the Braeval Mining Corporation.

He was captured by guerrillas in northern Colombia on January 18 along with two Peruvians and three Colombians employed by the Toronto-based mining company.

The South Americans were freed a month later, but the ELN hung on to Wobert, demanding that the company give up its mining rights.

Top ELN commander Nicolas Rodriguez said in comments on the group’s website ahead of the release that it was a “humanitarian act” that he hoped would be seen as a “contribution for peace in Colombia.”

Santos had said last week that Wobert’s release would be a step in the right direction to starting talks between Bogota and the ELN, which has some 2,500 fighters.

Since November, the Santos government has been engaged in talks with the country’s largest rebel group, the Revolutionary Armed Forces of Colombia, or FARC. The talks have taken place in Cuba.

Before the negotiations started, the FARC renounced kidnappings and freed its last police and military hostages in April of last year.

The reform allowing guerrillas who disarm to take part in politics has strings attached.

For instance, weapons have to by physically turned over and systematic war crimes and crimes against humanity must be probed and prosecuted, the Constitutional Court said.

The president has said this reform is the legal basis for the talks with the FARC.

Most FARC leaders have been convicted in absentia of one crime or another.

Santos wants a peace accord by the end of the year. He said seeing guerrillas convicted of terrorism transformed into politicians will be hard to digest for some Colombians but they have to give up something in the interest of peace.

“That is the bottom line of any conflict that you want to resolve. How much is society willing to sacrifice?” he told reporters Thursday.