California Gov. Gavin Newsom this week signed into law legislation that authorizes him to approve agreements allowing cannabis shipments across state lines. Industry advocates say that’s just the latest in a series of legal and political developments that could soon lead to the creation of interstate cannabis markets.

Jason Horst of Horst Legal Counsel and Adam Smith, founder of the Alliance for Sensible Markets, predicted that cross-national cannabis trade could start within a year, with or without a formal federal blessing.