[JURIST] Colorado Governor John Hickenlooper [official website] on Tuesday signed a new set of laws regulating the use and sale of recreational marijuana. One law expands [HB13-1317, PDF] the medical marijuana enforcement division [official website] to encompass retail marijuana. The law also prohibits retail marijuana stores from selling more than one-fourth of an ounce of marijuana to nonresidents. Another law, subject to voter approval in the November statewide election, imposes a 15 percent sales tax [HB13-1318] on retail marijuana or retail marijuana products and distributes 10 percent of the total tax revenue among the state’s local governments containing at least one retail marijuana store. A third law [HB13-1325, PDF] provides that drivers who are found to have five nanograms or more of delta 9-tetrahydrocannabinol [BMC Medicine article] per milliliter in whole blood may be charged for DUI.

The sale and use of marijuana remains a controversial issue in the US and abroad. Earlier this month the Supreme Court of California ruled [JURIST report] unanimously that local governments may outlaw medical marijuana dispensaries, upholding a ban enacted by the city of Riverside in 2010. In February the Michigan Supreme Court ruled that the private sale of medical marijuana is illegal [JURIST report]. Additionally, the top court in Ontario upheld Canada’s general ban on marijuana [JURIST report]. In December an Arizona judge ruled that the state’s medical marijuana law is constitutional [JURIST report] and instructed the state to permit dispensaries to open. In November lawmakers in Uruguay proposed legislation for state-regulated marijuana [JURIST report]. Also that month Washington and Colorado legalized the drug [JURIST report] via state ballot initiatives. Similarly, medical marijuana was legalized in Massachusetts [Harvard Crimson report] for the first time, as over 60 percent of voters approved a similar referendum.