Apportioning the blame properly is crucial to understanding the significance of this call from the WHO. The vast majority of responses to this article focus on for profit prisons, police lobbying, and how the government doesn't do what the people want. If these are the driving forces behind the drug war, then a WHO recommendation is going to have little effect. However, the emprical evidence shows that the drug war arose not from for profit prison lobbying, an industry that really didn't exist when the phrase was coined, but on the back of vast public support. Moreover, the evidence also shows decriminalization policies gaining ground as public opinion shifts.
The bottom line is that the thesis underlying most of the comments in this thread is wrong. For profit prisons, police unions, etc, are not the biggest roadblocks to legalization. They're opportunists, but the backbone of the drug war is massive support from soccer moms and dads, the reliable voters that created the drug war in the first place. And if the medical community starts chipping away at them, change will follow, regardless of what the prison lobbey wants.