There’s a new development in the unlikely alliance between potrepreneur Jamen Shively and former Mexican President Vicente Fox. Beginning on Thursday, Shively and the former president’s foundation, Centro Fox, are putting on a three-day symposium in Mexico devoted to discussing marijuana legalization and medical use.

The symposium follows a surreal press conference held by Shively in May, in which the former Microsoft manager and founder of Diego Pellicer announced his grand ambitions to create an international brand of premium pot. His star guest was Fox, who flew in to express his support for Shively and his hope that the events unfolding here in the wake of marijuana legalization would start a debate in his own country. The two men know each other from a time that Shively spent in Mexico running a business of cybercafes and computer centers.

Fox, with Shively’s help, is now stirring that debate himself. According to a preliminary program, the symposium in the central Mexican city of Guanajuato will feature panels of 20 American and Mexican experts discussing topics like “global experiences and new solutions for the legalization of drugs.” A final presentation of “conclusions and recommendations” is to be jointly given by Fox and Shively.

One surprising panelist will be Alison Holcomb, drug policy director of the ACLU of Washington and the former campaign manager of marijuana legalization Initiative 502.

At the time of Shively’s press conference in May, Holcomb expressed criticism of the man who talked about “minting more millionaires than Microsoft” in what he called the “dot bong era.” She warned that Shively’s expansionist plans risked provoking the federal government. Speaking with Seattle Weekly this week, she says she was also wary that Shively’s grand plans would lead to aggressive advertising targeting young people, a strategy once honed by alcohol and tobacco companies.

Holcomb and her allies in the 502 campaign sold legalization on the premise that it would be balanced by controls on advertising, a strong DUI provision and an age limit of 21.

But Holcomb says she was lured into participating in the Mexican symposium by its emphasis on public education and policy. “What I hope will happen is that there will be a conversation about what does a responsible marijuana business look like,” she says.

Holcomb also says she wants a chance to sit down with Shively. “I still don’t have a good sense of what exactly Jamen has in mind,” she says. “I’m wondering if he’s working that out himself.”