Charles Fain Lehman flouts the basic rule that correlation isn’t causation by linking short-lived drug decriminalization in Oregon and Washington to rising violent crime (“This Is the Pacific Northwest on Drugs,” op-ed, Aug. 7). But there’s no plausible reason that people who use drugs nonviolently would suddenly turn violent simply because they’re no longer jailed for possession. Even the study Mr. Lehman cites doesn’t blame drug use itself. Its authors suggest other causes: weakening social cohesion, failure to jail chronic offenders and broader “de-policing.” None point to drug use as the driver. Portugal’s drug decriminalization in 2001 didn’t cause an increase in crime; nor did the Czech Republic’s nine years later.

Mr. Lehman also blames the rise in overdoses on decriminalization. Yet a recent study from Brown University and RTI International researchers finds no link between Oregon’s Measure 110 and the state’s rise in overdose deaths. The authors accounted for fentanyl’s arrival, which moved east to west and hit the Pacific Northwest around 2019–20, causing the same overdose spike seen elsewhere. Once fentanyl was factored in, the association between decriminalization and overdose deaths disappeared. The real driver was the shifting drug supply.

Rather than imprison peaceful residents for using a substance the government disapproves of, Portland and Seattle should have enforced public nuisance laws, which the Supreme Court recently affirmed in Grants Pass v. Johnson (2024). Such statutes have roots in English common law and ought to be administered rationally and nonviolently.