Legalized marijuana spreads to two more states and D.C. Next up, California.

The legalize marijuana movement received a giant boost Tuesday.

Oregon and Alaska approved recreational pot use – following Washington State and Colorado, which did the same in 2012 – and the District of Columbia approved legal marijuana possession but not sales, though the move could still be halted by the new US Congress.

Though medical marijuana was rejected in Florida, the steps by Oregon, Alaska, and the District add momentum to a movement that is eyeing California next.

“Who would have guessed three years ago that we would now have marijuana legalized in four states and the District of Columbia?” asks John Matsusaka, executive director of Initiative and Referendum Institute at the University of Southern California in Los Angeles. “The speed at which this once-fringe issue has gained popular acceptance and moved into the mainstream is stunning.”

Yet marijuana remains prohibited by the federal government, and the issue could come to a head in the District of Columbia. Congress can veto any Washington, D.C., legislation, and legalization of marijuana there could force conservatives' hand. Alternately, the next president could take a firmer stand than President Obama has.

“What happened in Colorado and Washington in 2012 was unprecedented, now we’re adding Alaska, Oregon, and Washington, D.C., into the mix,” says Beau Kilmer, co-director of the RAND Drug Policy Research Center. “But don’t forget, this is still all illegal under federal law. The Obama administration is tolerating these experiments, but there will be a new president in January 2017. The federal approach can change.”

The three measures that passed Tuesday are:

• Oregon Measure 91 legalizes recreational marijuana for people ages 21 and older, allowing adults over the age to possess up to eight ounces of "dried" marijuana and up to four plants. The measure also tasks the Oregon Liquor Control Commission with regulating sales of the drug.
• Alaska Measure 2 allows people age 21 and older to possess up to one ounce of marijuana and up to six plants. It also makes the manufacture, sale, and possession of marijuana paraphernalia legal.
• Washington, D.C., Initiative 71 fully decriminalizes marijuana in the district, following a law passed earlier this year making possession of one ounce or less a ticketable infraction with a fine of $25. The ballot measure removes any penalty for possession or non-commercial transfers.

While Florida failed to legalize marijuana for medical use, the bar was high. The initiative needed 60 percent voter approval to pass. It garnered 58 percent.

Pro-marijuana forces took encouragement from that majority vote.

“This isn’t a rejection of medical marijuana in Florida, but an affirmation,” says Paul Armentano, deputy director of the National Organization for the Reform of Marijuana Laws (NORML). “The majority of Floridians, like the majority of voters across this nation, support patients’ access to medical cannabis, and we hope that the 2015 legislature will act on behalf of the will of the majority of the electorate.

Another initiative is being prepared for California’s 2016 ballot.

“It seems like just a matter of time before California joins the club,” says Professor Matsusaka

But anti-legalization groups are digging in because of Tuesday’s returns.

Kevin Sabet, co-founder of anti-legalization group Smart Approaches to Marijuana, told Reuters his group would significantly increase its efforts to build a broader coalition to beat back pro-cannabis groups – which are better funded – ahead of what is expected to be an expanded fight in 2016.

"Tonight is going to inspire us to do better and to try harder and go after the donors we have to go after in order to level the playing field," Mr. Sabet said. "The more people that hear about legalization, the more people are uncomfortable with it. For us, it's about getting our message out."

But Matsusaka suggests the momentum might be stronger than any attempt to stop it.

“With medical marijuana legal in half the states and recreational marijuana now legal in four states, it is hard to avoid the conclusion that popular opinion is evolving toward legalization,” he says.

Early fears that Washington and Colorado would encounter huge problems are not proving to be true, he adds. “The beauty of our federal system is that we have policy experiments in individual states. If the legalizing continues not to have the epidemics of crime and addiction that opponents have forecast, we will see more and more voters interested in going down this path.”