Iván Duque has few regrets from his time as Colombia's president. But if he could go back and do better on one thing, perhaps he should have been more vocal on the War on Drugs.

For Duque, there's too much focus on the supply side of the problem — Colombian cocaine — and too little attention on the demand side: Americans hungry for the drug.

In a GZERO World interview, Duque tells Ian Bremmer that he brought this up with both Donald Trump and Joe Biden. Maybe, he adds, he should have said it more and raised his voice.