Attorney General Eric Holder gave a green light on Thursday to two states whose efforts to legalize marijuana had been locked in by legal uncertainty for more than nine months. With that announcement, Colorado and Washington -- both of which passed pro-pot initiatives at the polls last November -- can now proceed with establishing a framework for the taxation and regulation of legal weed for adults.

The administration's decision holds clear and immediate implications for the two states, both of which had been hesitant to act too quickly over concerns that the government might decide to enforce federal law, which still considers marijuana an illegal substance.

But the move also, and perhaps more importantly, throws open the gates for other states to pursue similar pot legalization efforts, so long as they include "strong and effective regulatory and enforcement systems." Experts on both sides of the issue have already said they expect to see movement come quickly.

A similar pattern held for medical marijuana. The movement made steady progress up until 2009, when the Obama administration announced it would allow states to implement medical pot laws without federal interference. That promise turned out to be heavily footnoted, but the pledge itself ushered in a flood of ballot and legislative activity that burst the medical marijuana dam over the next four years. Thursday's announcement can be expected to do the same.

Public support for legal pot has surged in recent years at both state and nationallevels, with a majority of U.S. voters now in favor. This suggests that legalization would be most viable in states that allow citizen ballot initiatives. State lawmakers could also potentially take the reins on legalizing cannabis as the issue becomes more mainstream, however, like they did in New Jersey in 2010 with the passage of a bill approving medical marijuana.

Political dynamics are at play, too. Democratic strategists hoping to goose youth- and liberal-voter turnout in 2014 are incentivized to put pot on the ballot, though weed advocates themselves are better off running campaigns during presidential years, when the electorate doesn't skew as elderly as it does during midterms.

Below, the states that are most likely to take the next steps toward legalizing marijuana:

Alaska

Marijuana reformers in Alaska have been hard at work trying to make their state the next to legalize pot. In June, a ballot measure to tax and regulate pot and legalize it for adult recreational use was certified. Organizers must now collect at least 30,169 valid signatures of registered Alaska voters by December 2013, which would ensure that the initiative receives a vote in the primary election on Aug. 19, 2014.

Pot has already been decriminalized and legalized for medical use in Alaska. A survey of Alaska voters taken earlier this year by Democratic-leaning Public Policy Polling found that 54 percent supported legalizing marijuana.

Arizona

In June, marijuana legalization proponents began a campaign to gather the 259,213 signatures they'll need in order to get the issue on the 2014 ballot. The language of the proposed measure is rather expansive, and also includes a system of state taxation and regulation.

Marijuana was legalized in the state for medical use in 2010 by ballot initiative. A poll taken earlier this year found that 56 percent of Arizonans supported legalizing some amount of cannabis.

California

A statewide initiative to legalize marijuana failed in California in 2010, but reformers are hoping to find success in 2014 and beyond. Earlier this month, organizers filed the California Hemp Act 2014, a measure that would legalize cannabis both in its standard and non-psychoactive forms. Beginning Oct. 1, the campaign will have 150 days to gather 750,000 valid signatures from California voters in order to get the issue on the 2014 ballot.

Marijuana has already been decriminalized and legalized for medical use in California. A poll taken earlier this year found that 54 percent of Californians support legalizing pot.

Nevada

Marijuana advocates in Nevada have yet to mount a large-scale effort to get legalization on the ballot in an upcoming election, as most organizers in the state see 2016 as their best chance for a push. The liberal bent of the state makes it a popular target for reformers, however, and it's not yet clear whether Thursday's DOJ decision could increase desire for more immediate action.

Nevada has legalized medical marijuana, and earlier this year the state passed a measure establishing a dispensary system to help increase access for sick citizens. According to a recent poll, 56 percent of Nevadans would favor legalizing cannabis for recreational use if the money raised went to fund education.

Oregon

Medical marijuana legalization advocates in Oregon have already announced plans to campaign for an initiative to be placed on the ballot in 2014. An earlier legalization effort, which was poorly coordinated and widely mocked inside the state, failed in 2012. Organizers believe there is plenty of room for improvement.

Oregon has already decriminalized marijuana and legalized it for medical use. According to a poll taken in May, 57 percent of likely voters in Oregon support a proposal to tax, regulate and legalize marijuana for recreational use.

Maine

The Marijuana Policy Project, a pro-pot advocacy group, has announced Maine as one of its top targets for legalization in upcoming election cycles. An initiative circulating through the state Legislature fell painfully short in a state House vote earlier this year, but MPP has announced plans to help coordinate a grassroots campaign to get a legalization measure on the ballot in 2016.

Marijuana has been decriminalized and approved for medical use in Maine. According to a PPP poll released this week, 48 percent of registered voters in Maine believe pot should be legal for recreational use.

Massachusetts

The deep-blue New England state is being eyed as a prime opportunity for legalization, with marijuana reform advocates pointing to high margins of support for previous pro-pot initiatives. No official campaign for a ballot initiative has been launched yet, though many predict it is only a matter of time.

Massachusetts has decriminalized marijuana and just last November passed a ballot measure legalizing it for medical use. A February PPP poll found that 58 percent of the state's residents would be in favor of legalizing, taxing and regulating cannabis.

Montana

Montana has had a checkered history with marijuana laws. Voters passed an initiative legalizing cannabis for medical use in 2004, but opponents have since taken various steps to amend the measure or repeal it all together. Reform advocates remain hopeful that voters will support full legalization. They wasted no time following the 2012 election, filing a ballot question in hopes of putting the issue before voters in 2014.

There are no recent statewide surveys to gauge current support for pot legalization, though previous polls have showed a majority of Montana voters supporting the decriminalizing of marijuana.

Rhode Island

Marijuana advocates have high hopes that Rhode Island will be one of the first in the next round of states to legalize. This could come through a ballot initiative, but Rob Kampia, the executive director of MPP, recently said the issue could be ripe for state lawmakers to take on. While there's not yet a high-profile campaign to get legalization on an upcoming ballot, the state Legislature did consider a bill on the matter last session. While lawmakers debated the legislation and invited witnesses to testify on its merits, they never held a vote.

Rhode Island recently decriminalized marijuana and passed legalized medical marijuana around 2007. A PPP poll taken in January found that 52 percent of voters in the state support legalizing pot for recreational use.

Vermont

Vermont has made strides to scale back marijuana prohibition over the past year, with a successful measure to decriminalize and a separate bill to establish a system of dispensaries for the state's medical cannabis patients. Observers see the state's strong support for the recent reelection of Gov. Peter Shumlin (D), an advocate for marijuana reform, as a sign that voters could get behind a ballot initiative to legalize. There is no large-scale effort toward this end yet, but a legalization bill was introduced in the state Legislature last session. It didn't receive a vote.

Polls have consistently shown Vermonters to be supportive of efforts to scale back prohibition on marijuana.