The chief architect of Obama-era policies that largely shielded marijuana-legal states from heightened federal scrutiny said the decision by U.S. Attorney General Jeff Sessions to rescind that guidance will create uncertainty in an industry craving stability.

James Cole, now a partner at Sidley Austin in Washington, was the deputy attorney general in 2013 who wrote the guidance—known widely as the Cole memo—that told U.S. attorneys to focus on drug cartels and cross-border trafficking, not marijuana outlets complying with state regulatory schemes.