United States President Donald Trump has summoned four South American leaders to join him Monday afternoon in New York – hours before delivering his first speech before the 72nd United Nations General Assembly.

Among a range of hemispheric issues to be discussed is the surge of Colombian coca, as well as the on-going economic and political crisis in Venezuela. Colombia’s Juan Manuel Santos, Peru’s Pedro Pablo Kuczynski, Brazil’s Michel Temer, and Panama’s Juan Carlos Varela were called upon by Trump one month after the region’s leaders flatly rebuked a comment by Trump that a “military option” against the government of Nicolás Maduro was not being ruled out. Then, last week, a bombshell in the bilateral relations between the United States and Colombia – one of Washington’s closest allies – was dropped when Trump delivered a memorandum to U.S Secretary of State Rex Tillerson, in which the president “seriously considered” decertifying Colombia in its counternarcotics efforts.

The U.S certification process of Colombia as a strategic ally in the fight against drug trafficking and interdiction has not been called into question since the mid-1990s, when President Ernesto Samper Pizano saw his visa revoked by the United States after an investigation revealed illegal campaign financing by the Cali drug cartel. Samper, who won a narrow margin in the 1994 general elections over Conservative Andrés Pastrana, denied the charges, claiming he had run a legitimate and clean campaign. Eighteen months after taking office, the U.S Department of State stripped Samper of his travel visa.

Trump’s threat to decertify Colombia could have wide ranging implications for financing the so-called War of Drugs, cutting aid destined for illegal crop substitution projects, reducing the number of visa applications for citizens wanting to travel and study stateside, as well as potentially barring the entry of legitimate agricultural goods to the United States. Colombia and the United States signed a Free Trade Agreement in 2012.

During the administrations of Presidents Bill Clinton, George W.Bush and Barack Obama, Colombia has received its certification in the fight against drug trafficking and interdiction efforts. But as Colombia embarked on a peace process with the former Revolutionary Armed Forces of Colombia (FARC) guerrilla, the country saw a sharp increase in the coca harvest, cocaine production, especially after the nation’s security forces and world’s oldest Marxist insurgency forged a bilateral ceasefire.

Trump’s memorandum marks an ominous return to the days in which the main talking point between the United States and Colombia was drugs and the yearly certification approval. After more than two decades in which the word “certification” hasn’t been used against Colombia, last week’s memo threw into question the U.S-Colombia partnership and this country’s unwavering compliance with U.S drug policy. One of the reasons U.S officials cite for a 130% increase in coca production was Santos’ decision back in 2014 to ban the use of the herbicide glyphosate in aerial anti-drug crop spraying.

The Colombian President based his decision on research by the World Health Organization that classified the herbicide as a carcinogen that causes a wide range of illnesses, including cancer. The peace talks with FARC in Havana, Cuba, hailed the government’s decision to suspend spraying as a victory for the preservation of this country’s biodiversity.

In the memorandum to Tillerson, Trump claims that one of the reasons Colombia was not removed from the 22-nation list was because the National Police and Armed Forces “are close law enforcement and security partners of the United States.” The president, however, has not ruled out that he would keep the option open to decertify Colombia if it does not make “significant progress” in reducing coca cultivation and cocaine production. According to a 2016 report by the United Nations Office on Drugs and Crime (UNODC), the number of hectares cultivated for coca was 146,000 for that year, and 52% increase over 96,000 in 2015.

A 2016 report by the U.S State Department’s Bureau of International Narcotics estimates the number at 188,000 hectares.

The Santos government tried to defuse the decertification threat last week releasing a statement that claims “Colombia is without a doubt the country which has fought drug issue the most” and in direct reference to Trump: “No one has to threaten us to confront this challenge.”

From New York on Monday, Santos told Bloomberg that neither Colombia nor its neighbors – Peru, Ecuador and Brazil – support a military option against Venezuela. When asked about the surge in cocaine production and decertification issue, the president remarked that there is “co-responsibility” between the United States as a consuming nation and Colombia. “We have been working together for 30-years and need to continue to work together,” he said.