Fox, who was visiting San Diego Thursday to raise funds for his presidential library, was a U.S. ally in the war on drugs but has become an outspoken advocate of legalization, along with some other former Latin American leaders.
He blamed the United States for doing too little to cut domestic consumption and to stop the flow of weapons to Mexico, the Los Angeles Times reported.
"We're talking about the last frontier of prohibition," Fox said. "Tell me something else that is prohibited today? Abortion is permitted. Marriage between same-sex [people] now is permitted … smoking cigarettes is permitted, alcohol is permitted."
Fox's support for legalization prompted Point Loma Nazarene University earlier this year to rescind an invitation for him to speak at its San Diego campus.
During this visit, Fox spoke at a meeting of the American Society of Newspaper Editors and at the Trans-Border Institute at the University of San Diego.