On September 26, 2016, Colombian President Juan Manuel Santos and the head of the FARC—Rodrigo Londoño, alias "Timochenko"—signed the final agreement in a ceremony held in the port city of Cartagena, henceforth known as the Cartagena Agreement. On October 2, 2016, a peace plebiscite vote was held. On December 13, 2016, the Colombian Constitutional Court approved the fast-track mechanism for swift implementation of the peace accord between the Colombian government and the FARC. Colombia's Internal Armed Conflict and Key Players

Colombia, a longtime U.S. ally, has long been riven by internal conflict. In June 2000, the U.S. Congress approved legislation in support of Plan Colombia, providing $1.3 billion for counternarcotics and related efforts in Colombia and neighboring countries, which began a multi-year effort with the United States as the major international funder. When the exploratory talks between the FARC and the government were announced by President Santos in late August 2012, the ELN leader expressed an interest in joining the process that was acknowledged by the President. The negotiations with the FARC began following the government and FARC's agreement to a bilateral cease-fire, with a small demilitarized zone established in the municipality of La Uribe in the Meta department, long a FARC stronghold. Out of these preliminary discussions, the government and the FARC leadership agreed to a framework for formal peace talks that began in Norway in October 2012. In June 2012, the Colombian Congress approved another government initiative—the Peace Framework Law. Colombia's warming relations with neighboring Ecuador and Venezuela also seemed to have laid the groundwork for the peace talks. Although the negotiators from the other insurgent group, the ELN, and the Santos government continued their "preparatory" talks for formal negotiations in parallel with the FARC-government peace talks, nothing was announced during the year. In September 2015, President Santos met with FARC chief Timochenko in Havana. Santos and Timochenko publicly shook hands and announced that a final agreement would be signed not later than March 23, 2016. On December 15, 2015, the FARC and government negotiating teams signed a partial agreement on victims of the conflict, providing a comprehensive system for reparation, justice, truth, and guarantees for non-repetition and outlining a transitional justice system. On January 25 th , the U.N. Security Council adopted Resolution 2261, which committed a U.N. mission to monitor and verify a definitive bilateral cease-fire, once it was negotiated. The proposed funding for the Obama Administration's initiative was $450 million, $391 million of which was requested in the FY2017 congressional budget justification for foreign operations. A continuing resolution passed by Congress on December 9, 2016, funds assistance programs to Colombia at slightly below the FY2016 level ($300 million) through April 28, 2017, with the balance of FY2017 assistance levels to be determined after the 115 th Congress takes office. The U.S. Congress continued to express bipartisan support for the peace process at various points. On July 18, 2016, the Colombian Constitutional Court approved a peace plebiscite that would allow Colombians to vote on the agreement. The court also ruled that the vote would be binding on the executive branch. On August 24, 2016, the two sides reached the long-awaited final accord. Colombian voters surprised many on October 2, 2016, when, by a margin of 54,000 votes (out of 13 million cast) they rejected the original peace accord negotiated by the Santos government and the FARC. Without the public's backing, the government's investment in the process could be challenged, especially in the first critical year. The delegates of the Government of the Republic of Colombia (National Government) and the Revolutionary Armed Forces of Colombia-People's Army (FARC-EP):
As a result of the Exploratory Meeting held in Havana, Cuba, between 23 February 2012 and 26 August 2012, that counted on the participation of the Government of the Republic of Cuba and the Government of Norway as guarantors, and on the support of the Government of the Bolivarian Republic of Venezuela as facilitator of logistics and companion: 
With the mutual decision to put an end to the conflict as an essential condition for the construction of stable and lasting peace;
Attending the clamour of the people for peace, and recognising that:
construction of peace is a matter for society as a whole that requires the participation of all, without distinction, including other guerrilla forces that we invite to join this effort;
respect of human rights within the entire national territory is a purpose of the State that should be promoted; 
economic development with social justice and in harmony with the environment is a guarantee for peace and progress; 
social development with equity and well-being that includes big majorities allows growing as a country; 
a Colombia in peace will play an active and sovereign role in peace as well as regional and worldwide development;
it is important to broaden democracy as a condition to build solid foundations for peace.
In August 2012, Colombian President Juan Manuel Santos announced that the government was engaged in exploratory peace talks with the violent leftist insurgent group, the Revolutionary Armed Forces of Colombia (FARC), in a bid to resolve a nearly 50-year internal armed conflict. The secret, initial dialogue between the Santos government and the FARC's leadership led to the opening of formal peace talks with the FARC—the oldest, largest, and best-financed guerrilla organization in Latin America. Formal talks began in Oslo, Norway, in October 2012 and then, as planned, moved to Havana, Cuba, where they continued for more than 50 rounds.
Despite more than three years of negotiations, the leader of the FARC, Rodrigo Londoño, alias "Timochenko," had not met publicly with President Santos. In September 2015, the two leaders shook hands in a televised meeting and announced that the negotiating parties would reach a final accord no later than March 23, 2016. However, that deadline, as many others before it, went unmet. By the end of 2015, the most difficult issue in the peace talks' agenda, outlined in a framework agreement, was resolved. Government and FARC negotiators reached a partial agreement on victims of the conflict, providing a comprehensive system for reparations, justice, truth and guarantees for non-repetition and outlining a transitional justice system.
In late January 2016, the United Nations (U.N.) Security Council adopted Resolution 2261, stating that a U.N. mission would monitor and verify a definitive bilateral cease-fire and cessation of hostilities between the parties, following the signing of the final peace agreement. Terms for operationalizing the accord were announced in June 2016, when the Santos government and the FARC agreed to a bilateral cease-fire, security guarantees for demobilized guerrillas, mechanisms for dismantling paramilitaries, and the location of demobilization zones. On July 18, 2016, the Colombian Constitutional Court approved a peace plebiscite as the appropriate mechanism for the public to endorse or reject the final agreement arrived at in Havana. The court also determined that the plebiscite vote would be binding for Colombia's executive branch.
In a surprise loss, on October 2, 2016, the first accord—known at the Cartagena Agreement—was rejected in a peace plebiscite, defeated by 54,000 votes out of 13 million ballots cast. In November 2016, the government and the FARC signed a second accord, which the government maintained responded to criticisms of the "No" campaign leaders, who objected to the first accord. The Colombian Congress approved the second accord, and the Colombian Constitutional Court upheld the fast-track mechanism that would have allowed rapid implementation of the Cartagena Agreement was upheld to apply to the second accord on December 13, 2016.
The Santos Administration had anticipated the peace process with the FARC by proposing several legislative reforms that were enacted in the first years of Santos's first term (2010-2012), including a law to restitute victims of the conflict and a "peace framework" law. In addition, the warming of relations with neighboring countries, such as Ecuador and Venezuela, helped to lay the groundwork for the peace process. Venezuela, Chile, Cuba, and Norway also actively supported the process, which most countries in the region have lauded.
The U.S. Congress remains deeply interested in Colombia's political future, as the country has become one of the United States' closest allies in Latin America. Congress has expressed that interest by its continued investment in Colombia's security and stability. Over the years, the U.S.-Colombian relationship has broadened from counternarcotics to include humanitarian concerns; justice reform and human rights; and economic development, investment, and trade. Peace Colombia, the assistance program proposed by the Obama Administration, foresaw a peace accord with the insurgents building on many gestures of support made by the Administration. The initiative was designed to help Colombia secure peace with $450 million of support, $391 million of which was requested in the FY2017 congressional budget justification. A continuing resolution passed by Congress on December 9, 2016, funds assistance programs to Colombia at slightly below the FY2016 level ($300 million) through April 28, 2017, after the 115th Congress takes office.
This report provides background on Colombia's armed conflict and describes its key players. The report briefly analyzes prior negotiations with the FARC and the lessons learned from those efforts. It examines what transpired during the preparatory negotiations and four years of formal talks that led to the final accord with the FARC. The report also examines some of the constraints that could limit the success of the peace accord's implementation and the possible influence of implementation on future U.S.-Colombian relations.