Just because voters legalized marijuana doesn't mean the illegal drug economy will just go away.

The Washington State Liquor Control Board's "pot czar" claims tax revenue from state marijuana stores will only be about half of what was promised... if that.

Mark Kleiman, a drug policy expert at UCLA, says the state-run system won't produce the results promised by I-502 (the legal measure that legalized it).

Those pushing the bill said legalizing and taxing marijuana would not only get rid of the black market, but would result in $450 million a year in new tax dollars. Kleiman says that's not going to happen.

Illegal drug deals will continue to operate in the background and if not dealt with will leave Washington state with two conflicting marijuana economies.

According to the Tacoma News-Tribune, because of the medical marijuana law, dispensaries (especially in Seattle) have been allowed to operate freely. Kleiman says many of them are fronts for recreational pot sales.

The marijuana law passed last November sets aside millions of dollars for medical use, schools and marijuana education. It was supposed to squeeze out illegal pot. But the bill doesn't do much for enforcement. As the Tacoma News-Tribune pointed out, the state has to shut down the medical dispensaries, and crack down on black-market illegal private dealers.

As the News-Tribune put it:

The idea behind the initiative was to replace illegality with legality, and reduce the use of marijuana. But the measure may wind up reducing the stigma and cost of the drug as the black market continues to boom – the worst of both worlds.