Is it capitulation when Mexico, which faces an existential threat from drug cartels, decides to decriminalize drugs?

Is it cynicism when California, which faces a budget crisis, considers legalizing and taxing marijuana?

Quips are easy. But the problems are complex, and we are about to get a look at the consequences, for good or bad, of what happens when governments relax their drug laws. It is a moment for studied observation.

Mexico's new law decriminalizes small amounts of marijuana, cocaine, heroin, LSD and methamphetamine. Those caught will be told to seek treatment the first two times; treatment is mandatory the third time.

Under previous laws, possession could lead to long jail terms. Treating drug abuse as a social and public-health problem rather than a law-enforcement issue is expected to free up prison space and resources to go after criminal drug cartels, according to Mexican officials.

It may seem contradictory to excuse the user while targeting suppliers. But in Mexico, which has long supplied the U.S. market for illicit drugs, domestic consumption is a relatively new phenomenon. According to government statistics, the number of addicts in Mexico has risen by more than 50 percent in six years.

Will Mexico's new policy result in more addicts seeking treatment, or will it create an atmosphere in which more people become addicts? Will Mexico provide the necessary treatment for the 300,000 to 465,000 addicts estimated to be in the country? Will this change in policy legitimize the drug cartels? Or help Mexico's aggressive campaign against these criminal syndicates, which are responsible for more than 11,000 deaths since 2006?

Arizona's shared border with Mexico also raises concerns about the impact on U.S. visitors to Mexico, particularly spring-break revelers.

Arizona's western border offers the chance to observe another experiment in moving away from a law-and-order model for dealing with drug use.

In 1996, California voters approved medical marijuana. The needed prescription is a small fig leaf that covers a wide variety of "ailments."

California Assemblyman Tom Ammiano, a Democrat, proposes full legalization of marijuana for adult use, with regulation and taxation. A tax of $50 per ounce is estimated to raise $1.3 billion annually. According to one poll, 56 percent of California voters support such a plan.

There also are three initiative efforts in California to put marijuana-legalization measures before voters in November 2010.

Again, there are more questions than answers.

Both California's move toward legalization and Mexico's experiment with decriminalization provide real-life laboratories for observing the effects of new approaches to drug use. We'll be watching.