After 10 months as a hostage, former Colombian congressman Odín Sánchez is finally free. Sanchez had been a captive of the National Liberation Army (ELN) since last April when he exchanged his freedom for that of his ailing brother, Patrocinio. This—along with the other prisoner exchanges that followed—is an encouraging sign of good faith in the peace talks, which began last week.

Still, the challenges are immense. Uncertainties and political issues within the government and the ELN could complicate the upcoming talks, and the political climate following the recently completed negotiations with the Revolutionary Armed Forces of Colombia (FARC) present significant challenges to the budding peace negotiations.

These negotiations are no small task to begin with. The ELN is one of many armed leftist groups that appeared in Colombia during the 1960s. The group is second only to the FARC in manpower (unofficial army estimates put the total at around 1500) and is financed similarly through kidnapping, extortion, drug trafficking, and illegal mining. Known for its high profile infrastructure attacks, the ELN has taken responsibility for numerous bombings on electrical plants and oil pipelines. The group has resurged in the last eight years after being relatively inactive from 2003 to 2009.

The government first attempted to negotiate with the group in the 1970s when President Alfonso López Michelsen reached out to the ELN, as well as several other militant organizations, in an effort to bring them to the negotiating table. Since then, six other administrations have attempted and failed to reach an agreement with the group. President Juan Manuel Santos, however, has much more riding on these negotiations than his predecessors—his legacy as president, and as the winner of 2016 Nobel Peace Prize, rests on the long-term sustainability of peace.

For Santos, though, his own political challenges could prove to be one of the biggest obstacles to an accord with the ELN. In the aftermath of a razor-thin defeat of an original accord with the FARC in an October referendum, Santos’ political capital is nearly spent. A recent survey released by Datexco reports that 69% of Colombians have an unfavorable view of the President. To make matters worse, allegations recently surfaced that the Santos’ re-election campaign may have received up to $1 million from Brazil’s Odebrecht SA, currently at the heart of a massive continent-wide corruption scandal. While the allegations are based on testimonies from individuals associated with an opposition party, they still represent yet another bump in the road for Santos.

Meanwhile, Colombian society remains bitterly divided and cynical about the future. While 80% of Colombians are supportive of peace negotiations with the ELN, 46% are pessimistic about the country achieving lasting peace with the two major guerrillas. 61% of Colombians believe that the ELN has no real intentions of signing a peace agreement.

Santos is aware of the challenges ahead, and is taking extra steps to restore confidence in the upcoming negotiations. He has appointed a top-tier negotiation team that includes former ministers, politicians, and experts, and even called on former President Álvaro Uribe to appoint a member of the team. Uribe, though, may have little political motivation to participate. The former president famously opposed the deal with the FARC and became the face of the “No” campaign preceding last year’s plebiscite. With the 2018 elections upcoming, Uribe and his party’s eventual presidential candidate—whoever it may be—can be expected to rally opposition to Santos on all fronts, including on the ELN talks. The elections themselves are almost certain to be a referendum on Santos’ peace processes. This presents a timing problem for the government. There is a risk that President Santos will have to hand over the negotiations to a successor who doesn’t share the same vision for the process.

To make matters worse, the ELN has credibility problems of its own. Compared to the FARC, the group is less vertically structured and internally cohesive. The organization is currently composed of six rural fronts and one urban front. Each front tends to operate autonomously from the national command and the organization’s national leaders have limited, if any, power over the group as a whole. In fact, even releasing Congressman Sánchez was a complex and halting process. The Cimarron Front, based out of Choco, was reluctant to release Sanchez without payment, and stalled his liberation in spite of direct orders from the organization’s commanders. As with any peace processes, the interests of upper level officers and foot soldiers may not always be aligned—but in this case, lack of agreement along with weak command structures may continue to undermine the negotiations.

Finally, even as Santos grapples with the ongoing political challenges in the wake of the agreement with the FARC, the process with the ELN may be hampered by the accord’s successes on the ground. Even though the ELN has agreed to talks, incentives for the guerrillas to remain active will be higher than ever. For most of the organization’s history they have trailed behind the FARC in numbers as well as territorial control. Now that the latter is demobilizing, the temptation for the ELN to attempt to occupy the resulting vacuum will be strong. This is further exacerbated by the deteriorating situation in Venezuela, which has opened up new drug trafficking routes and markets for smuggling of basic goods like food and gasoline.

Altogether, the challenges are daunting. For peace to be achieved, both sides will have to take significant risks. ELN leaders will have to forge a consensus among the multiple fronts in order to best represent a unified set of goals and compromises. The stated goals of the ELN tend to be much broader and more generalized than those of the FARC, which make specificity and consensus all the more important. For the government, success will require bridging the divide among a sharply polarized electorate. Without sustained and widespread public support, even with the inevitable setbacks and tough concessions to come, the long-term success of the process is in jeopardy.  Although most Colombians are supportive of peace talks, the specifics could make or break the entire process—much as happened in the negotiations with the FARC. In simple terms, if the public decides too many concessions are being given to the guerrillas, the accord may not survive. 

If there is one silver lining for Santos, it is that his political weakness may prove to be a negotiating tool of sorts. If the ELN truly wants an accord—and is capable of reading Colombian politics to any degree—they must reckon with how weak the president’s hand currently is, how limited his ability to compromise has become. It would be smart for the guerrillas to focus on a few realistic goals instead of pushing too many issues and accommodations. The group also should do far more to convince the skeptical Colombian electorate that they come to the table in good faith.

In all likelihood, the only possible agreement with the ELN will be one that the Colombian people perceive as less generous than the one signed with the FARC. Peace, for these particular guerrillas, will come at a price.