Voters for an Arizona measure that would legalize medical marijuana have pulled ahead in the tally of ballots, after trailing in early counting: Votes for Proposition 203 now lead by 4,421, with 1.63 million counted. (On Nov. 2, votes against the measure led by about 7,200.) About 10,000 votes remain to be counted, almost all in Maricopa County, which includes Phoenix. Proposition 203 would allow patients with cancer, HIV/AIDS, Hepatitis C, or any other "chronic or debilitating" disease to buy 2.5 ounces of pot every two weeks or to grow marijuana plants. If the measure passes, Arizona will become the 15th state to permit marijuana use for medical purposes.