Colorado and Washington voters have passed historic measures to legalize marijuana for recreational use by adults in their respective states. Massachusetts became the 18th state to put some form of a “medical marijuana” law on the books.

Colorado’s Amendment 64, which permits the “personal use and regulation of marijuana” for adults 21 and over, was passed with a 53 to 47 percent margin, making Colorado the first state to end marijuana prohibition in the country.

Washington voters passed Initiative 502, which regulates and taxes sales of small amounts of marijuana for adults, by a 55.5 to 45.5 percent margin. Under the Washington law, adults in the state may possess up to an ounce of marijuana, 16 ounces of marijuana products and 72 ounces of liquid infused marijuana products.

While Massachusetts voters approved Question 3, enabling doctors to recommend marijuana as part of a treatment plan, similar measures were rejected by Oregon and Arkansas voters.  (Oregon’s Measure 80 would have permitted both commercial and unlicensed growth of marijuana and its sale to and use by adults. It also would have created an administrative structure for licensing or regulating the sale of marijuana.) Oregon likely will revisit the issue, either in the legislature or the next election cycle.

The effects of the legalization of marijuana in Colorado and Washington will be watched closely.  The measures conflict with federal Controlled Substance Abuse Act, which defines marijuana as an illegal drug. The Administration has opposed legalization in the past, but remained silent on the marijuana-legalization initiatives throughout the run-up to the balloting. Nevertheless, we expect legal challenges as the newly authorized, state-regulated marijuana markets begin to take shape