By a 17-point margin, Oregonians approved Ballot Measure 110, which eliminated criminal penalties for possessing small amounts of any drug, including cocaine, heroin, and methamphetamine. When the policy went into effect early the next year, it lifted the fear of prosecution for the state’s drug users and launched Oregon on an experiment to determine whether a long-sought goal of the drug-policy reform movement—decriminalization—could help solve America’s drug problems.

Last year, the state experienced one of the sharpest rises in overdose deaths in the nation and had one of the highest percentages of adults with a substance-use disorder. During one two-week period last month, three children under the age of 4 overdosed in Portland after ingesting fentanyl.