Last fall, a prominent Seattle pot lawyer named Jeffrey Steinborn predicted doom for Initiative 502, the ballot measure that legalized marijuana in Washington State: "I truly believe that when this law passes, a legal challenge by the Feds will pretty much void all of it," he said. Steinborn's point was that, even though he supported legalizing marijuana, the measure would overstep Washington State's authority by attempting to license pot farms and pot stores. Not only would federal prosecutors sue our state, he believed, the initiative would be "a law enforcement sting in plain sight" for anyone who tried to open a pot business.

That argument made for bizarre bedfellows. Other pot activists picked up Steinborn's rallying cry, with one organization calling the initiative a "house of cards in a windstorm." A passel of former federal antidrug officials made this argument their primary talking point in a conference call with reporters last fall, in which they urged the president to oppose the initiative in Washington and a similar measure in Colorado. "Federal law, the US Constitution, and the US Supreme Court decisions say that this cannot be done because federal law preempts state law," said former DEA administrator Peter Bensinger at the time.

In addition to legalizing personal possession of marijuana, the initiatives were written in a way that would replace the illicit pot market with a legal one—thereby ending the need to arrest dealers and growers (which pot activists like), while also cutting off cash to gangs that profit from illegal pot sales (which antidrug officials like). But these ambitious initiatives could clash with the federal Controlled Substances Act, meaning that the greatest strength of a fully fledged replacement for the drug war—a regulatory model that cuts crime, raises taxes, and gets dealers off the street—would also be its greatest weakness in federal court.

So what happened when voters in Washington State and Colorado handily passed both initiatives last November? How did the Feds actually respond when state officials began a rule-making process this year to license pot farms, certify distributors, and let pot stores open? We finally got the answer last Thursday, when President Obama and Attorney General Eric Holder announced that they would let the initiatives stand. That alone was stunning news, and before we move on, let's just pause to appreciate it: Entrepreneurs in Washington and Colorado will be growing large-scale recreational marijuana farms by next year, and adults will be buying pot in stores.

This is a real thing that is happening.

Under presidents Nixon, Carter, Reagan, Clinton, Bush, and Bush junior, pot busts more than doubled and then doubled again. The FBI reported 853,000 pot busts nationwide in the year 2010 alone—a year when pot arrests accounted for 52 percent of all drug arrests. That is, most of the drug war on US soil was about busting people for pot (disproportionately racial minorities). The White House drug czar's office has also spent years fighting attempts to legalize marijuana, most recently opposing initiatives in California and Nevada, with a deluge of threats that federal law would preempt any state reforms. But now, President Obama has grabbed the steering wheel and taken America on a hairpin turn.

By standing back and letting Washington and Colorado implement these new laws, Obama has declared that the US drug war is not mandatory. If a state can present a comprehensive legal framework as an alternative—an alternative to the abstinence-only model—the president is saying, in essence, he'll let the states try it.

States can opt out of the drug war, in other words.

This is radical.

The federal government has espoused only one message for decades when it comes to recreational drugs: You can never use them. And for decades, every state was required to fall in line.

But at least for this administration, the president will formally defer to the states on drug policy, much the way the federal government now defers to states on marriage equality. So last week's news is about more than just two states and two pot initiatives. Defying the expectations of lawyers and antidrug hawks, this president will now let the states replace the drug war with something entirely new.

"If you step back, we're talking about ending the war on drugs, and the federal government has given a green light to the states to try different approaches," says Alison Holcomb, a lawyer who works for the ACLU of Washington and drafted Initiative 502, which contained exactly that strict framework for marijuana that the Feds have tacitly endorsed. "That is much bigger than legalizing marijuana in Washington and Colorado."

But Obama has a few caveats, of course. On the phone with the governors of Colorado and Washington, AG Holder explained the US Justice Department would not sue Washington and Colorado for preempting the federal Controlled Substances Act, provided that the states do two things: (1) strictly enforce their own laws that regulate the pot market, and (2) abide by eight federal conditions. The weightiest of those conditions are preventing pot from leaking outside state borders, not allowing unregulated cannabis commerce, and banning access for minors. Those are admittedly tall orders. But what wasn't in those conditions stands out dramatically. Holder didn't tell states to prevent massive regulated pot farms, to ban wholesale marijuana distribution, or to prohibit storefronts selling marijuana just like bottles of wine. Those are also major violations of federal law—technically—but the Feds are, stunningly, groovy with them if the farms, distribution, and sales are done in compliance with state laws.

After the talk with Holder, Washington State governor Jay Inslee explained his understanding of the deal in a press conference: "If you are following Washington State law and following these eight rules, and our state follows them as well, we are going to have a successful program here—and successful business," he said.

This signals a deliberate decision about who is in charge of large-scale drug enforcement. "The thrust is that they will allow the state of Washington to be the principal law-enforcement agent in this regard," Inslee said. That is, for the first time, the president and head of the US Department of Justice have chosen to hand over the reins on major, controversial drug-control policy to the states.

(A quick aside about medical marijuana: Under Obama, the Feds have raided hundreds of medical marijuana cooperatives, mostly those that don't comply with state guidelines. Still, the vast majority of patients, growers, and cooperatives have not been busted. Most of them do business without a lick of penalty. The difference in this case is that medical marijuana is a much smaller market than recreational marijuana, and medical marijuana has a much higher level of public support. This time around, the pot in question has no pretense of medical need.)

To catch up with the new decree for recreational pot, Deputy Attorney General James Cole emphasized state control last Thursday in a memo to federal prosecutors about how to handle prosecutions in "jurisdictions that have legalized marijuana in some form." While the memo says prosecutors can bust offenders at their discretion (a boilerplate caveat), Cole essentially instructed prosecutors to butt out if states have their own "strong and effective regulatory and enforcement systems." Cole added that even large-scale marijuana businesses—marijuana agriculture, essentially—would not be a priority if conducted in compliance with the state guidelines.

So, if the Obama administration is handing over the reins to the states, where can those states go with it? Holcomb, the ACLU lawyer, says that courts, treatment centers, and communities can begin crafting new policy. "And we should not be shy about doing it."

In my opinion, this could extend to states decriminalizing hard drugs, counties diverting hard-drug dealers into treatment programs instead of jail, or cities opening supervised-injection sites for heroin users—all basic reforms that many have feared could clash with federal law. Or even more simply, this tells dozens of other states that they can pass their own legalization initiatives.

So why would Obama open this floodgate?

First, there's no guarantee that a federal challenge of state pot laws would win in court. State bureaucrats issuing licenses and enforcing rules for the industry doesn't necessarily create a so-called positive conflict with federal drug laws (state employees would not necessarily be handling the marijuana).

But second, Obama's decision seems even more tactical than legal. The purported goals of the drug war have been to reduce access to kids, cut off profits to organized crime, and make streets safer—but the drug war has been a renowned failure at achieving those goals. Kids can buy pot at school, cartels are getting rich, and drug-related violence is commonplace enough to become banal. A damning Rasmussen poll released last November found that only 7 percent of American adults think we are winning the war on drugs, 82 percent say were are losing it, and 12 percent didn't know.

Colorado and Washington essentially forced the federal government's hand to see who has a better proposal. The states have contended that they can implement a tight regulatory framework that will more effectively reduce violence and drug abuse. And as a result, the Feds folded. It was an unprecedented admission that the White House is paralyzed in its drug-war straitjacket, the federal drug war failed, and they are ready to work in tandem with states that have more flexibility.

Of course, if Washington's and Colorado's legal weed starts showing up in California, if kids start buying pot at the stores in significant numbers, or if people with licenses are running shady profit deals outside the regulatory scheme, you can be sure the Department of Justice will seek an injunction against the states to shut this down. They still may not win, but they will have grounds to try.

This was a political gift to Obama. He's a liberal, ultimately. And as our first black president, he wants ineffective drug laws dismantled as a means toward racial justice and economic stability. But he needed it dismantled by someone else.

Zooming out to look at the drug war internationally, the US has been breathing down the necks of other countries to stop them from legalizing marijuana, too. I called the cell phone of Ethan Nadelmann, director of the Drug Policy Alliance, a preeminent authority on drug strategy in the US and abroad, as he was sitting in a car driving down a narrow, winding road in Jamaica between Kingston and Negril. He'd spent the day before in conference with members of Jamaica's past and current cabinet, and members from dueling political parties, to talk about legalizing ganja. He said some were uneasy about it; a few years ago when the issue came up, the US ambassador made imposing phone calls.

"To the extent that they are no longer scared of the call from the ambassador or of losing trade preference, to the extent that other countries feel less intimidated, I think this announcement today is significant internationally," Nadelmann said. "State Department officials have no credibility to criticize marijuana reform in other countries when the US is leading the way on marijuana law reform."