THE DISTRICT’S law decriminalizing small amounts of marijuana went into effect only in July, but already voters are being asked to take the even more far-reaching step of legalizing the drug. We supported the elimination of harsh criminal penalties; jailing people who smoked pot and saddling them with criminal records made no sense and resulted in the unfair targeting of young black men.

But the rush to legalize marijuana gives us — and we hope voters — serious pause. Marijuana, as proponents of legalization argue, may or may not be less harmful than alcohol and tobacco, both legal, but it is not harmless. Questions exist, so it would be prudent for the District not to make a change that could well prove to be misguided until more is known. Foremost here are the experiences and lessons learned by states that have opted for legalization.

Initiative No. 71, the Legalization of Possession of Minimal Amounts of Marijuana for Personal Use Act of 2014, will appear on the Nov. 4 ballot and, if approved, would make it lawful for a person 21 years or older to possess up to two ounces of marijuana for personal use, grow up to six plants at home and transfer without payment up to one ounce of marijuana to another person 21 years or older. Because of the District’s restrictions on what is subject to ballot approval, the initiative would not allow for the sale of marijuana, but initiative backers say they would expect the D.C. Council to address this and other issues with legislation.

It’s instructive that the council, in assessing the city’s approach to marijuana enforcement, chose the more cautious path of decriminalization rather than outright legalization. Voters would do well to consider the reasons for that caution.

The American Medical Association has come out against legalization, arguing that “cannabis is a dangerous drug and as such is a public health concern.” The active ingredient in marijuana has been linked to memory problems, impaired thinking and weakened immune systems, not to mention it acts as a gateway to more dangerous drugs. Dangers are more pronounced for young people. A study just published in the Lancet Psychiatry reported that teenagers who smoke marijuana daily are 60 percent less likely to complete high school. Advocates of legalization say it would not apply to young people but with legalization inevitably comes a message of approval.

It’s not been a year since Colorado became the first state to allow recreational marijuana use and, as the Smart Approaches to Marijuana has catalogued, there have been negative consequences, including increased instances of impaired driving and increased use by youth. With marijuana already decriminalized, there’s no reason for the District to rush the next step; why not at least give Colorado a bit more time to provide lessons?

D.C. voters should vote no on Initiative No. 71 on Nov. 4.