How marijuana became legal

The acceptance of medical marijuana has implications that extend far beyond helping those suffering from life-threatening diseases. It is one of several factors -- including demographic changes, the financial crisis, and the widely perceived failure of the war on drugs -- reopening the country's 40-year-old on-again, off-again shouting match over whether marijuana should be legalized.

This article is not another polemic about why it should or shouldn't be. Today, in any case, the pertinent question is whether it already has been -- at least on a local-option basis. We're referring to a cultural phenomenon that has been evolving for the past 15 years, topped off by a crucial policy reversal that was quietly instituted by President Barack Obama in February.