Just this week Ron Paul and Barney Frank introduced a bill to roll back a substantial portion of the federal War on Drugs---specifically to get the federal government out of the marijuana prohibition business and let the issue decamp to the several states. Indeed this is where I as a reactionary believe that the issue belongs. The various states ideally exist precisely because everyone doesn't like the same flavor of ice cream and relocating within the US is far less disruptive for people and cultures than outside of it. I have the same take on a lot of other issues, including the ever controversial abortion issue.
On the side of the ledger favoring rolling back this part of the War on Drugs, I have this:
Instituting a law where a strong, practically universal moral consensus does not exist always causes significant damage to the fabric of a society, both from the resentment of the losing party and through the efforts by the winning party to coerce the dissenters. Sometimes it is worth it, but the reactionary at least should be aware that it is an act of war in any reasonable calculus, and consider both which wars and the number of his wars very carefully indeed.
I'm not going to belabour the point that in any honest reading of the US Constitution that Prohibition Part II would require a bona fide amendment. An honest reading of the US Constitution hasn't been had since at least 1920, and it wasn't universal by any means even then. Stare Decisis might be popular among conservatives, but I'm a reactionary and know a one-way ratchet when I see one.
There is also the massive increase in the size and scope of government which has come as an auxillary to the drug war. Not just in prisons, law enforcement, and hordes of administrators---it also strengthens a strong urge in the conservative to show that he's not just a 'meanie' and aggravates the perceived need to 'buy peace' (and votes of course) through social spending.
That disputes and control in the insecure property rights framework that traffickers in drugs work within is frequently fought over with guns and knives instead of lawsuits and buying local politicians is beyond question. The end of Prohibition I caused a significant fall in crime, and not just in the trivial (i.e. crimes involving alchohol directly).
On the negative side
The population in favor of this is one not friendly to the cause of reaction. That is, they generally don't like us and we don't like them. This isn't an overriding consideration, but it should never be underestimated. The business of government and politics is, at least since the 1930s, the rewarding of friends and the punishment of enemies.
Drug possession is a crime that many criminals can be charged with without the necessity of cooperation by witnesses in hostile NAM neighborhoods with Stop Snitching is a strong meme.
It's a difficult call honestly. Were the population in question more allied with the cause of reaction, it'd be a 'no-brainer'. As it is I'm willing to support removing marijuana from the War on Drugs.