April 20th has become an unofficial holiday for advocates of the legalization of marijuana. Temple history professor David Farber says the mainstreaming of the phrase reflects a change in public attitude. “First of all, so many Americans have at one time or another indulged in this illegal activity. And while some people suffer adverse effects or use it too regularly, I think most Americans think of it as really, in some ways, a milder intoxicant than alcohol. So I think it’s really just kind of a democratic process,” he said.