Tomorrow, voters in four states will decide how the next chapter of marijuana reform will be written. If several of the measures pass, it will likely build momentum for a growing public consensus on legalization. On the other hand, if all or most of the measures fail, legalization proponents may need to take a step back and reassess their strategies for legalization efforts already planned for a number of states in 2016.

It took a certain amount of audacity to put marijuana on the ballot in 2014 to begin with. Support for marijuana legalization is heavily concentrated among younger and more liberal voters, while midterm electorates are by definition older and more conservative than those in presidential years. There's some evidence that marijuana ballot measures bring younger voters to the ballot booth: exit polls show that in Colorado and Washington, young voters made up a larger share of the electorate in 2012 (when marijuana was on the ballot) than in 2008.

On the other hand, an analysis by FiveThirtyEight earlier this year used Current Population Survey data to explore a number of different elections where marijuana was on the ballot and found that differences in young voter turnout were negligible. So it's unclear whether this year's ballot measures will bring more young voters to the polls.

Here's a rundown of where each of the four ballot measures stand.

D.C. - full legalization

Likelihood of passage: high

D.C. voters will choose whether to allow adults 21 and over to legally possess up to two ounces of marijuana, and grow up to six plants. Polling has shown consistently high support for the measure - at this point, it would be a major surprise if it didn't pass.

The drama will come after the vote. The D.C. council is expected to put in place a framework to allow the legal sale of marijuana, following Colorado and Washington's lead. The council held a hearing on the issue last week. Councilman David Grosso has already drafted a bill that would tax recreational sales at 15 percent and put regulation in the hands of the city's alcohol regulators.

Looming over it all is the specter of congressional interference. Maryland Representative Andy Harris tried - unsuccessfully - to block the implementation of the city's decriminalization measure earlier this year. He's already said that he will "consider using all resources available to a member of Congress" to stop any full legalization efforts. Given the current state of gridlock in Congress and the lengthy to-do list facing the lame duck session when members return, it's unclear how much luck he'd have.

Legal weed in the nation's capital would be a huge symbolic victory for marijuana reformers. And a showdown with Congress over implementation could be a political minefield for opponents of legalization and their allies on the Hill. Reformers would be all too happy to characterize their opponents as thwarting the will of the people, and a recent YouGov poll suggests they'd have an easy time doing so: a majority of Americans say Congress should not interfere with legalization efforts in DC.

Oregon - full legalization

Likelihood of passage: probable

When voters in Colorado and Washington passed marijuana legalization bills in 2012, true-blue Oregon was the odd man out: its Measure 80 failed at the polls. News outlets called the bill "wacky," noting that the bill itself contained references to George Washington and cited the "herb-bearing seed" of the Book of Genesis.

As my colleague Emily Badger wrote last month, legalization proponents are taking a wholly different approach this time around. They're calling their current bill "the most regulated and strict marijuana measure ever voted upon in Oregon," and are strongly emphasizing regulation and taxation as part of legalization. They're selling it as the marijuana legalization initiative for people who don't want to smoke marijuana - and who don't want their kids to, either.

Most polls show the measure ahead. The latest SurveyUSA poll has it passing with 52 percent support.

Alaska - full legalization

Likelihood of passage: too close to call

Alaska voters will also decide whether to fully legalize marijuana tomorrow. Alaska's situation is unique because the personal possession of up to four ounces of marijuana has been protected under the state's constitutional right to privacy since 1975. This puts more headwind in front of legalization efforts, since a certain number of voters who would otherwise support a legalization bill might decide that the current protections are sufficient.

Alaska already has one of the highest marijuana use rates in the U.S. These users could turn Alaskan weed into a $107 million industry if legalization passes and puts a $50 tax on marijuana at the wholesale level. But polls show an incredibly close contest, with small nuances in how the questions are worded yielding very different responses. At this point its anyone's game.

Florida - medical marijuana

Likelihood of passage: ¯\_(ツ)_/¯

In June, Florida governor Rick Scott signed a bill that would allow a non-psychoactive strain of cannabis known as "Charlotte's Web" to be used to treat patients with epilepsy. Voters are now deciding whether to approve a fairly wide-reaching medical marijuana measure that would allow doctors to recommend marijuana for any "conditions for which a physician believes that the medical use of marijuana would likely outweigh the potential health risks for a patient."

As a constitutional amendment, the measure requires 60 percent support to pass. Polls have been all over the map on this one, with different surveys showing 20 percentage point differences within just a few days of each other. While Floridians overwhelmingly approve of medical marijuana in theory, it's safe to say that they're conflicted about the merits of this particular bill.

Florida's campaign is also the most expensive marijuana ballot measure this year. Casino magnate Sheldon Adelson has poured $5 million of his own money into the opposition campaign, fueling it almost single-handedly. On the other hand supporters have raised about $8 million, roughly half of it from attorney John Morgan.

While the fate of the other marijuana initiatives rests largely in the hands of young voters, Florida's seniors may be the lynchpin here. Given the volatility of the polls it's very difficult to predict how things will play out, but the 60 percent supermajority requirement represents a high bar for supporters of the measure.