You gotta think about it though: What else CAN be done, prohibition aside?
A jail term might be too lenient for certain cases. Look at the 10 or so countries in the world which have already implemented capital punishment as one of the consequences for drug trafficking. The activity there is especially low, and for a couple, practically non-existent or completely underground.
It may sound harsh, but its one of the ways to get results.
It depends. Singapore is one of the most crime-free societies on the planet, but they also have no personal freedom, can't chew gum, and can be killed for having a doobie. Would never work in the States.
There have to be tiers to any democratic punishment system. Serious drug traffickers I wouldn't mind seeing getting capital punishment. However, the appeals process in the States will tear that up. It obviously isn't fair for people that have one kilo of coke to get the death penalty, but people with 9/10ths of a key cannot. And high school kids that are smoking pot can't go to jail with hardened criminals. That isn't rehabilitation, thats criminal breeding. Too many gray areas in drugs for capital punishment.
An alternative is the tack that Argentina is taking. They're proposing laws decriminalizing use and possession of small amounts of marijuana. "[We]...conclude that the (highly unlikely) risk of addiction is an acceptable ‘cost’ for the benefits gained."
They're hoping to isolate the hard drug users and traffickers from the rather large marijuana user base.