Ten years ago, Colorado voted to legalize marijuana. To honor the anniversary, Sen. John Hickenlooper (D-colo.) has proposed a bill designed to take effect if and when marijuana is federally legalized. His legislation would set up a commission to draft rules and regulations, which Congress and the bureaucracy could put into effect once marijuana is dropped as a Schedule 1 drug under the Controlled Substances Act.

Here’s a better idea: Don’t legalize marijuana.

Where states have legalized marijuana, the promised reduction in crime has completely failed to materialize. In many cases, the tax revenues have also been disappointing. But that is only the beginning of the problem.

The most common practical outcome in states that legalize is that the legal marijuana trade struggles or flops in contrast to a growing and flourishing illegal marijuana trade. The illegal trade, as a practical matter, can no longer be controlled because reduced criminal penalties have “lowered the cost and risk of doing business.”

As a result, state and local authorities find themselves ill-equipped to crack down on ubiquitous illegal rural grow sites, as the Los Angeles Times reported. By the Los Angeles Times’ account, these illegal grows have brought with them to rural areas “cannabis-related violence, bringing shootouts, robberies, kidnappings and, occasionally, killings,” such that locals are now afraid to venture out at night.

Meanwhile, the number of crashes caused by impaired driving due to marijuana since legalization has more than doubled, according to various studies that focused on the blood content of either injured or dead drivers.

The most alarming thing about marijuana legalization is that its advocates dishonestly conceal and obscure the fact that for those under age 30, frequent marijuana use can permanently hinder brain development. It causes lasting damage to the frontal cortex, which is “critical to planning, judgment, decision-making, and personality,” as well as the hippocampus, which controls memory, balance, and coordination.

Finally, it must be said that a marijuana joint is not medicine any more than chewing medicinal bark is medicine. Modern medicine insists on controlled doses so as to cause minimal side effects.

This is why pills were created, to harness the medicinal power of various plants and other substances and deliver them gradually in carefully measured amounts as they dissolve in your stomach. Cannabis probably does have valuable medicinal properties. Indeed, pills already do exist that deliver most of the known ones. The idea of smoking a cigarette to improve your health is ridiculous, probably more ridiculous than chewing tree bark, come to think of it.

Moreover, multiple studies have shown that even the medical use of marijuana is harmful, even when it is prescribed by a doctor. According to a study by the National Bureau of Economic Research, it is also “associated with higher opioid mortality.” That is, it is a gateway to other even more dangerous drugs, as its critics always contended and its defenders always denied.

The legalization of recreational marijuana, the same study said, is “associated with greater death rates relative to the counterfactual of no legal cannabis.”

Ten years of legal marijuana has not caused a collapse of civilization, but it is definitely harming people’s lives. It is probably also creating a future class of brain-addled government dependents with a tendency toward psychosis and poor judgment. Congress should ignore Hickenlooper’s proposal and resist the temptation to greenlight legal cannabis use nationwide.

Ten years of legal marijuana has not caused a collapse of civilization, but it is definitely harming people’s lives. It is probably also creating a future class of brain-addled government dependents with a tendency toward psychosis and poor judgment.