At a ceremony held in Havana, Cuba, the leftist president said: “In the end, peace is built by correcting wrong paths and by building new ones, because there is nothing more revolutionary … than peace.”

The ceasefire is a major development for Colombia, as the country has only struck a bilateral agreement with the ELN once before. That was in September 2017, and it lasted just 101 days.

“It’s very significant for us because it could be the beginning of a scenario through which we could achieve much more,” said Mauricio Capaz, an Indigenous Nasa leader from the department of Cauca, where the ELN maintains an active presence.

The ceasefire will come into effect on August 3 and last for 180 days. It will be implemented gradually in three phases, allowing for the establishment of protocols, community dialogues and a comprehensive monitoring mechanism.

That monitoring will be led by the United Nations’ mission in Colombia, as well as the Catholic Church, to ensure compliance with international humanitarian law. If both the ELN and the government are satisfied with the ceasefire at the end of the six months, they can also negotiate to extend it.

“This process can help generate conditions for peace through which the country can take a new direction,” Aureliano Carbonell, a key ELN negotiator, told Al Jazeera from Havana.

‘Ambitious’ bid for peace

The government hopes the ceasefire will be instrumental in ushering in an era of “total peace”, one of Petro’s key campaign promises.

Colombia has been ravaged by nearly six decades of internal armed conflict, leaving at least 450,664 people dead and millions more displaced from their homes. Among the combatants are right-wing paramilitary groups, criminal networks, left-wing rebels and government forces, all vying for control over territory.

After a 2016 peace deal led to the disarmament of the Revolutionary Armed Forces of Colombia (FARC), the ELN took its place as the biggest remaining rebel group, with approximately 3,000 fighters.

That has made the ELN a key constituency in present-day peace negotiations. But progress has been fitful at best. The recent ceasefire has come after three rounds of talks in three different countries, stretching all the way back to October.

On December 31, peace with the rebel group finally seemed at hand, when Petro announced on social media a New Year’s Eve ceasefire with five armed groups, among them the ELN. But days later, the ELN denied any such agreement.

It was a setback for Petro, Colombia’s first leftist leader and himself a former M-19 guerrilla fighter. He had vowed to depart from the militarised approach used by previous Colombian governments to address the violence, committing instead to lead through negotiations.

“Petro’s peace approach is ambitious,” Jorge Mantilla, a Colombian political analyst and conflict scholar, told Al Jazeera. “But for the ELN, it’s important to keep in mind that there isn’t going to be a government that’s more open to making peace with them than Petro’s.”

Shortcomings to the negotiations

Despite the ceasefire’s significance, experts worry it may not be able to fully address the violence Colombia faces.

As it stands, the ceasefire is set to halt any fighting between the state and the ELN. But analysts say the tensions between the ELN and the government are no longer a focal point of the conflict, as the violence is instead driven by warring armed groups.

“The main deficit of this agreement is that it’s not a cessation of hostilities, which is really what is required in order to affect the humanitarian conditions on the ground. It’s strictly a ceasefire,” Elizabeth Dickinson, a senior analyst for Colombia at the International Crisis Group, told Al Jazeera.

Therefore, Dickinson warned, the ELN could still carry out intimidation campaigns against other parties, namely the civilian population and competing armed groups. The group’s tactics include territorial clashes, extortion, kidnapping, forced confinement, the recruitment of minors and charging protection money.

Such actions would contradict the international humanitarian law that governs the ceasefire. And with the Colombian government committed to avoiding violence with the ELN, Dickinson argues that state forces may focus more on their efforts to combat rival armed groups.

“It ends up providing a strategic advantage to the ELN in terms of their ability to consolidate their control on the ground, while doing very little to protect the communities who are living in these areas,” Dickinson said of the ceasefire.

The ELN leadership has yet to clarify whether it will suspend its hostile activities towards other armed groups. Carbonell, the ELN negotiator, told Al Jazeera, “It’s an issue that’s being worked on.”

“You can never really say that a given situation is not going to happen,” Carbonell said. “If one side does not comply, the other side is not obliged to, either. But we’re working so that this process is welcomed by the ELN as a whole.”

The Colombian government did not respond to Al Jazeera’s request for comment.

Lessons from previous peace attempts

There are also concerns about the implementation of the new ceasefire, as the country is wary of repeating the mistakes of the 2016 peace agreement with the FARC.

Some members of the FARC refused to disarm, instead forming their own dissident groups that continue to fight in the Colombian countryside. And in areas where the FARC did disband, rival groups have stepped in to claim the drug trafficking routes and territory that were left abandoned, creating lingering impediments to peace.

Capaz, the Indigenous Nasa leader, echoed Dickinson’s fear that the new ceasefire may allow the ELN to exert its influence without opposition from the state. But he also worried that a successful ceasefire could encourage rival groups to enter his native Cauca — as occurred following the 2016 agreement.

“The ceasefire is very good. It guarantees us some form of tranquility, but the reality here is that there is a strong confrontation between the ELN and other armed groups,” he said.

The ceasefire could create “another form of control from the armed groups”, he explained. “That’s the cruel paradox of reality here.”

Carbonell, however, said that the ELN leadership is eager to “learn from the experiences” of the 2016 agreement with the FARC. He added that the armed group was hoping the ELN’s process to be “a little different” than that of the FARC.

“When establishing peace processes, we have to try to make them of a higher quality than those that have been presented previously and had somewhat difficult results,” he told Al Jazeera. “It won’t be perfect. It might still have shortcomings due to the complexity of this entire process, but we aspire to have much more effective components.”

So far, both the government and the ELN leadership have welcomed the initial ceasefire agreement. For rural Colombians who live under the ELN’s shadow, however, their optimism is tinged with caution and the need for broader action.

“We cannot continue burying our dead or being displaced in order to discuss these kinds of issues that are structural and complicated,” Capaz said. “A multilateral ceasefire is fundamental.”