And perhaps most pressingly, will the Justice Department just stand by while the states issue licenses to the growers, processors and sellers of a substance that, under federal law, remains very much illegal?
"We're building this from the ground all the way up," said Brian Smith, spokesman for the Washington Liquor Control Board, which is charged with regulating the drug. "The initiative didn't just wave a magic wand and make everybody here an expert on marijuana."
The measures approved on Nov. 6 have two main facets. First, they OK the possession of up to an ounce of marijuana by adults over 21. That took effect Thursday in Washington, though it remains illegal - for now - to buy and sell pot, so people have to keep getting it from the marijuana fairy.
In Colorado, where pot fans will also be able to grow their own plants, the law takes effect by Jan. 5.
The other part of the measures, the regulatory schemes, are trickier. Washington's Liquor Control Board, which has been regulating alcohol for 78 years, has a year to adopt rules for the fledgling pot industry: How many growers, processors and stores should there be in each county? Should there be limits on potency? How should the pot be inspected, packaged, and labeled?
To help answer those questions, officials will turn to experts in the field - including police, public policy experts, and some of the state's many purveyors of medical marijuana.
With legalization, officials need to look at some of the measures that have been shown to reduce teen drinking, said Derek Franklin, president of the Washington Association for Substance Abuse and Violence Prevention. That includes public education about the risks of pot use and driving while stoned, emphasizing police patrols to look for stoned drivers, and encouraging cities to adopt laws that hold parents accountable if they host parties at which children are provided marijuana.