If Washington voters approve an initiative legalizing marijuana in November it will set national precedent, ending the decades-long era of drug busts and prosecutions for possessing limited amounts of the drug.

The question is: Will voters really decide the issue?

Federal law makes it illegal to possess, grow or sell any amount of marijuana.

If voters in Colorado and Oregon also approve similar measures this November, it is unlikely the federal government will simply sit on its hands and watch the drug be sold from storefront businesses.

“When states do that, the federal government will have to take a look and respond,” said John McKay, a Seattle University law professor and former U.S. Attorney. McKay has not only endorsed Washington’s legalization initiative but has become one of its leading public advocates.

Hugh Spitzer, who teaches state and federal law at the University of Washington’s law school, said a growing legalization trend among states could set off a tug-of-war over enforcement of marijuana laws with the federal government.

In part, Initiative 502 would allow people 21 and older to buy an ounce of marijuana from stores regulated and licensed by the state, where it would be taxed at 25 percent.

Currently, state law allows doctors to recommend marijuana for patients with a terminal or debilitating medical condition.

If Washington voters approve the initiative, neither state nor local law enforcement agencies will be charging people with marijuana crimes — as long as they don’t violate the law’s provisions, Spitzer said.

“That has no effect on federal laws that make it illegal to possess, grow or sell marijuana,” Spitzer said.

Federal officials declined to comment on the initiative or what steps they might take if it passes.

Department of Justice rules prohibit comment on state legislation, including Initiative 502, said Emily Langlie, a spokeswoman for the U.S. Attorney’s Office in Seattle.

“To predict how it would play out would be taking a position on the initiative,” she said.

The federal Drug Enforcement Administration has a similar stance.

“Marijuana is a violation of federal law and DEA enforces federal law,” spokeswoman Jodie Underwood said. “We do not speculate on pending legislation or state law.”

Pat Slack, commander of the Snohomish Regional Drug Task Force, said he asked Gil Kerlikowske, Seattle’s former police chief and the nation’s drug czar, about what steps the federal government might take.

Slack said Kerlikowske told him that no decision has been made because the issue hasn’t yet been decided by voters. “In other words, they aren’t getting into an ‘If the voters do this, we’ll do that’ game,’” Slack said.

However, in a 2011 letter to Gov. Chris Gregoire, U.S. Attorneys Jenny Durken and Michael Ormsby said that the Department of Justice remains firmly committed to enforcing federal drug laws in all states.

Earlier this month, federal law enforcement officials sent letters to 23 medical marijuana dispensaries in Seattle saying that any businesses within 1,000 feet of schools or playgrounds must shut down within 30 days.

State Rep. Marko Liias moderated a public forum on the marijuana initiative earlier this year in Mukilteo and has since endorsed the initiative. He said he thinks the federal government will take action to halt legalization if voters say yes.

“The federal government would argue that state law conflicts with federal law … and I think you would see them going to court fairly quickly,” he said.

The issue could ultimately be decided by the U.S. Supreme Court, he said.

Yet a majority of Supreme Court justices have shown great respect for the rights of states in the nation’s law making system, said Spitzer, who teaches at the UW law school.

The federal government cannot force a state to make marijuana illegal, he said. And it does not have unlimited resources to devote to marijuana prosecutions.

“I think federal law enforcement officials will try to engage in well publicized actions to discourage people from growing and selling marijuana, but they can only do that up to a point,” he said.

Spitzer said he sees efforts by states to legalize marijuana as having some parallels with what took place in the late 1920s and early 1930s during the late stages of prohibition.

The federal government relied on state officials to enforce prohibition, he said. Yet some states took action on their own to lift the ban on alcohol.

Washington was among them. Voters approved an initiative to end prohibition in 1932. The federal constitutional amendment repealing prohibition wasn’t ratified until December 1933, he said.

If three or four states pass marijuana legalization initiatives “it will be as hard to enforce federal marijuana laws as it was to enforce federal alcohol prohibition laws in 1932 and 1933,” Spitzer said.

McKay said he hopes that if states begin passing marijuana legalization laws that the federal government won’t interfere with such efforts and that Congress will pass laws freeing states to set policies.

“Congress and the federal government will revise its policies when states revolt against marijuana prohibition,” McKay said.

Sharon Salyer: 425-339-3486; salyer@heraldnet.com.