The promises of Colorado’s Amendment 64 largely hinged on two words blazing from campaign signs dotting the state before the historic November 2012 vote that legalized recreational marijuana for people 21 and older: Regulation works.

But how it would work was described only in general terms and sound bites before voters headed to the polls to make a decision Gov. John Hickenlooper later would call “reckless” and “a bad idea” and new Colorado Attorney General Cynthia Coffman declared “not worth it” to dozens of state attorneys general last month.