For decades it was one of Washington's closest alliances.

United in their fight against drug trafficking, Colombia and the United States co-operated closely, with the latter receiving hundreds of millions of dollars in US military assistance annually. But now that alliance appears to be more fragile than ever.

The leaders of the two countries may have similar forceful styles but left-wing Gustavo Petro and Donald Trump come from opposing ends of the political spectrum and have clashed frequently since Trump returned to the White House in January.

On Sunday, tensions peaked when Trump accused Petro of encouraging drug production in Colombia and announced the suspension of payments and subsidies to the South American country. This escalation followed Petro's accusations against US officials of murdering a Colombian citizen and violating sovereignty during strikes against alleged drug vessels in the Caribbean.

Experts warned that with the alliance in jeopardy, both Colombia and the US could suffer while organized crime groups look set to benefit.

Colombia became a main beneficiary of US aid in the early 2000s, with initiatives like 'Plan Colombia' aimed at combating drug trafficking groups and strengthening Colombian security forces. While it arguably weakened the Farc guerrilla group, doubts linger regarding its long-term efficacy against drug trafficking, especially as cocaine production in Colombia hits record levels.

Despite reduced US assistance, Colombia remains a crucial ally in America's fight against narcotics, with the country providing valuable intelligence for US operations. Yet, recent cuts and critiques—especially the Trump administration’s announcement of reducing aid—pose significant risks to both nations.

Compounding these issues, military strikes ordered by the US have drawn sharp criticism from Petro, who has branded them as acts of tyranny and called for accountability.

As both governments grapple with these tensions, the increasing likelihood of unrest and a resurgence of drug trafficking looms on the horizon. The once symbiotic relationship is in peril as criminal organizations may exploit the weakening ties between the US and Colombian leadership.