Originally appeared at: http://www.cbsnews.com/8301-504763_162-20022928-10391704.html (CBS/AP) If opponents of medical marijuana thought voters in Arizona would defeat Proposition 203, they must have been smoking something. On Saturday, Arizonans narrowly approved the measure, which will legalize weed for people with certain diseases. Final vote tallies showed that Prop 203 won by a tiny margin of just 4,341 votes out of more than 1.67 million votes counted. “Now begins the very hard work of implementing this program in the way it was envisioned, with very high standards,” said Andrew Myers, campaign manager for the Arizona Medical Marijuana Policy Project. “We really believe that we have an opportunity to set an example to the rest of the country on what a good medical marijuana program looks like.” Arizona is the 15th state to approve a medical marijuana law. California was first in 1996, and 13 other states and Washington, D.C., have since followed suit. The Arizona measure will allow patients with diseases including cancer, HIV/AIDS, hepatitis C and any other “chronic or debilitating” disease that meets guidelines to buy two and one-half ounces of marijuana every two weeks or grow plants. The patients must get a doctor’s recommendation and register with the Arizona Department of Health Services. The law allows for no more than 124 marijuana dispensaries in the state. Backers of Prop 203 argued that thousands of patients faced “a terrible choice” of suffering with a serious or even terminal illness or going to the criminal market for pot. They collected more than 252,000 signatures to put the measure on the ballot – nearly 100,000 more than required. But all of the state’s sheriff’s and county prosecutors, the governor, attorney general and many other politicians came out against the proposed law. Carolyn Short, chairwoman of Keep AZ Drug Free, the group that organized opposition to the initiative, said her group believes the proposed law will increase crime around dispensary locations, lead to more people driving while impaired and eventually lead to legalized pot for everyone. Another story about the passage of proposition 203 in Arizona legalizing medical marijuana.