SEATTLE (AP) — A man who once served as the Justice Department's top official in Seattle said Tuesday that he is sponsoring an initiative to legalize possession of up to an ounce of dried marijuana in Washington state, a measure he hopes will help "shame Congress" into ending pot prohibition.

John McKay spent five years enforcing federal drug laws as the U.S. attorney in Seattle before he was fired by the Bush administration in early 2007. He told The Associated Press on Tuesday that laws criminalizing marijuana are wrongheaded because they create an enormous black market exploited by international cartels and crime rings.

"That's what drives my concern: The black market fuels the cartels, and that's what allows them to buy the guns they use to kill people," McKay said. "A lot of Americans smoke pot and they're willing to pay for it. I think prohibition is a dumb policy, and there are a lot of line federal prosecutors who share the view that the policy is suspect."

McKay is joining Seattle City Attorney Pete Holmes, travel guide Rick Steves and the state chapter of the American Civil Liberties Union in forming a group called New Approach Washington. They're pushing an initiative to the Legislature that would regulate the recreational use of marijuana in a way similar to how the state regulates alcohol. Their bill would legalize marijuana for people over 21, authorize the Liquor Control Board to regulate and tax marijuana for sale in "standalone stores," and extend drunken driving laws to marijuana, with blood tests to determine how much of pot's active ingredient is present in a driver's blood.

New Approach Washington planned a news conference Wednesday to announce the effort. No state has legalized marijuana for recreational purposes in such a way, though some have decriminalized it, and the initiative would put Washington squarely at odds with federal law banning the drug.

The legislation would set limits on how much cannabis people can have: an ounce of dried bud, 16 ounces of marijuana-infused foods in solid form, and 72 ounces of marijuana-infused liquids, or all three, said Alison Holcomb, drug policy director of the ACLU of Washington. The limits are necessary to help ensure that people don't buy large amounts for resale in other states, she said.

The bill would not allow for the recreational growing of marijuana; it would be up to the state's Liquor Control Board to license grow operations and set limits for how large they can be. The measure would not affect the rights of medical marijuana patients in Washington, who are allowed to have at least 24 ounces and 15 plants, and more if needed.

Activists would have until the end of this year to gather more than 240,000 signatures to get the initiative before the Legislature. Lawmakers will have a chance to approve it or allow it to go to the ballot.

Taxing marijuana sales would bring the state $215 million a year, conservatively estimated, Holmes said.

Another group, Sensible Washington, is already pushing a legalization initiative this year that would remove all state criminal and civil penalties for marijuana use, possession and cultivation in any amount. Their effort is an initiative directly to the voters, meaning that if it qualifies for the November ballot and passes, it would become law without any input from the Legislature.

Sensible Washington failed to gather enough signatures to make the ballot last year, and Seattle medical marijuana attorney Douglas Hiatt, who leads the effort, said Tuesday he did not know whether their measure would qualify this year. Hiatt criticized the approach of the ACLU-led effort, saying it wouldn't allow Eastern Washington's farmers to grow hemp or really end prohibition at all. Furthermore, he said, the blood test limit for driving under the influence purposes — 5 nanograms of active THC per milliliter of blood — are so strict that most medical marijuana patients would fail even if they hadn't recently medicated.

Last year in California, voters rejected Proposition 19, which would have allowed for personal possession and growing of limited amounts of marijuana, 54 percent to 46 percent.

In a telephone interview from Idaho, where he was about to leave on a six-day rafting trip on the Salmon River, McKay said he has long considered marijuana prohibition a failed policy, but that as U.S. attorney his job was to enforce federal law, and he had no problem doing so. Among the people he prosecuted was Canada's so-called "Prince of Pot," Marc Emery, who fought extradition after his 2005 arrest but eventually was sentenced to five years in prison for selling millions of marijuana seeds to U.S. residents.

"When you look at alcohol prohibition, it took the states to say, 'This policy is wrong,'" McKay said. "This bill might not be perfect, but it's a good step forward. I think it will eventually shame Congress into action."

Holmes said McKay's involvement in the legalization effort helps demonstrate its sensibility.

"Whether you are a Democrat or a Republican, in law enforcement or a medical provider, you look at the data and you come to the same conclusion: The war on drugs has failed," he said.