There are just a couple of weeks to go before recreational marijuana goes on sale in California. And there are almost as many unanswered questions now as there were when state residents voted to de-criminalize weed a year ago. The legalization of cannabis in America’s largest state, if carried off well, represents an opportunity to end the war on drugs that still rages around much of the United States. But a failed roll-out – one that keeps the black market for pot intact – would also have national implications. Zócalo Public Square columnist Joe Mathews says he's not confident that the state is ready for a smooth transition.