I though that conservatives opposed unconstitutional uses of federal power? Please site the part of the constitution that gives the federal government the power to make drugs illegal.
I don't think a specific reference to drugs can be found in the Constitution, no more than for city parking ordinances. Laws against drug use are a way of instilling a certain amount of "good behaviour" on the part of all. Reality, however, is not necessarily in agreement with the intended results.
To the extent drugs (whether legal or not) have the capacity to incite disorder and general lawlessness, not to mention health problems, the law acts as a "parent" to protect us from ourselves.
I have no doubt there are people who can exercise self-control in everything, including drug use. But they are probably few and far between, especially in light of the fact we elected Clinton TWICE. It is up to them to make a sensible case for legalization for the rest of us. The article above is a start.
As with alcohol, we'll still have people who do harm to others through negligence and abuse. We are debating how much potentially harmful intake we should allow for society in general; how we can live peaceably with the least amount of self-inflicted harm and the most liberty. Difficultfor either side not to have an agenda that goes against common sense.
Either way, the world isn't getting any better.