The U.S. opioid crisis is now driven by fentanyl, a powerful synthetic opioid that currently accounts for 90% of all opioid deaths. Fentanyl is smuggled from abroad, with little evidence on how this happens. We show that a substantial amount of fentanyl smuggling occurs via legal trade flows,...

Marijuana is partially prohibited: though banned federally, it will soon be available to almost 1 in 4 U.S. adults under state statutes. A chief concern among policy makers is marijuana trafficking from states with legal markets elsewhere. We measure trafficking with a natural experiment. Oregon...