In all the plague-ridden excitement, I've barely heard a word about drug possession becoming decriminalized in Oregon next year. My question: Does this sea change in market conditions mean that coke, meth and smack are about to get a whole lot cheaper? —Walter White Christmas

I'm not sure if this will come as good or bad news to you, Walter—my own opinion fluctuates based on how many drinks I've had in the past couple of hours—but fears that Oregon's new law will usher in an era of cheap, plentiful drugs are likely overblown.

At first blush, this doesn't make sense. Tougher drug laws make drugs harder to get, right? According to supply and demand, that should increase the price. Lenient laws, meanwhile, should make prices drop.

That's not what happens, though. As the prosecutors of the War on Drugs discovered, ramping up enforcement often has the paradoxical effect of driving drug prices lower. Drug availability actually increased in the tough-on-crime 1980s. The more you tighten your grip, Grand Moff Tarkin, the more star systems will slip through your fingers!

I'd be lying if I said there was a solid academic consensus as to why this happens, but there is one theory I find persuasive. Fire up a doobie and gather round! As a practical matter, tighter drug enforcement means jailing a lot of low-level drug dealers and dealer-users—the big fish rarely gets caught.

These small fish don't have a lot of clout, but they're an essential part of the drug supply chain, and the Pablo Escobars of the world couldn't make their millions without them.

When the cops crack down, however, being a Joe Schmo drug dealer becomes a riskier, less attractive proposition. To keep Joe working this now-crappier hustle, the big fish lowers his price, and the lure of fatter profits keeps Joe on the job.

Whether you buy that or not, other evidence points in the same direction. As it happens, Portugal decriminalized drugs in 2001, with a law similar to Oregon's. Drug prices there stayed largely unchanged.

All the efforts law enforcement has made over the years seem to have had little effect—in either direction—on this most implacable of free markets. I'm calling it: The War on Drugs is over. Drugs won.

Questions? Send them to dr.know@wweek.com.