REEFER GLADNESS, AS POT GOES LEGAL IN WASH.

SEATTLE -

People openly lit joints under the Space Needle and on Seattle's sidewalks - then blew the smoke at TV news cameras. To those looking to "get baked," the city's police department suggested pizza and a "Lord of the Rings" movie marathon.

What, exactly, is going on in Washington state?

Marijuana possession became legal under state law Thursday, the day that a measure approved by voters to regulate marijuana like alcohol took effect. It prompted midnight celebrations from pot activists who say that the war on drugs has failed.

But as the dawn of legalization arrives, Washington and Colorado, where a similar law passed last month, now face some genuinely complicated dilemmas: How on Earth do you go about creating a functioning legal-weed market? How do you ensure adults the freedom to use pot responsibly, or not so responsibly, while keeping it away from teenagers?

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 also will 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. Smith anticipates undercover monitoring operations to make sure that the private, state-licensed stores aren't selling to minors.

The marijuana will be taxed heavily, with revenues possibly reaching hundreds of millions of dollars a year for schools, health care, basic government services and substance abuse prevention.

Unless, of course, the Justice Department has something to say about it.