Coca in Peru and Colombia, and the stupidity of the war on drugs

"Why are Peru, Colombia Coca Numbers Going in Opposite Directions?"
That was the headline on a recent Insight Crime report. I am a fan of the site, which focuses on organized crime in Latin America and the Caribbean, offering valuable reporting and analysis.
But the answer to the question posed in that headline seems obvious.
Cocaine demand isn't going down. Market forces mean suppliers will find ways to meet the demand.
So if Peru is producing less coca, the leaves that end up as cocaine, Colombia or some other country will be producing more.
And Peru is producing less, thanks to government eradication campaigns. "Peru has reduced coca cultivation by almost one-third in the last five years, according to figures from the United Nations Office on Drugs and Crime, and in 2015 the country registered the lowest amount of coca sown in the last 15 years," the website reports.
But across the border in Colombia, things are different. Colombia went through its own eradication campaigns, cutting coca cultivation in half between 2007 and 2012.
The graph with the article shows the result. As Peru's cultivation went down, Colombia's increased to help meet the global demand for cocaine.
In 2011, the two countries had about the same number of hectares under coca cultivation, for a combined total of 126,200.
Last year, Peru's cultivation had been reduced by about 22,000 hectares and Colombia's had increased by 32,000 hectares. The combined total was 136,300.
The article offers some explanations for the trends, including community resistance to eradication efforts in Colombia and the involvement of FARC's left-wing guerrillas in production.
But the underlying reality has been established through almost a century of failed, wildly expensive efforts to deal with drug issues by limiting supply.
Cut production in one area, and another country will increase production to fill the gap. Make it harder to get heroin, and users will turn to prescription opiates. Crack down on the availability of those drugs, and fentanyl emerges as a more deadly alternative.
Attacking the supply side of the drug equation didn't work when the U.S. introduced Prohibition to end alcohol sales in 1920. It hasn't worked in the 45 years since U.S. president Richard Nixon announced a war on drugs.
Yet governments, including Canada, continue the costly, futile and ultimately destructive efforts, ignoring the obvious evidence of their failure, and the terrible damage that has been done.