In 1971, Richard Nixon declared a “War on Drugs,” kicking off a nationwide campaign criminalizing drug use and drug users. But today, more than 50 years later, weed is legal in almost half the country, the opioid epidemic has fundamentally changed the way we view addiction, and the War on Drugs is widely viewed as a glaring policy failure. Meanwhile, several countries across the world have legalized marijuana and even experimented with the decriminalization of all drugs. What is the future of legal and illegal drug use, and what can policymakers in the US learn from how other countries regulate drugs of all kinds?