There are very few political issues today which have not already become firmly entrenched along the same basic party lines that all our other political issues hew towards. In most cases, it's a matter of "Democrats believe X, while Republicans insist on Y." On one issue, though, there is a sizeable (and growing) bloc of voters who are not only cross-partisan but also so committed they could be called "single-issue voters." I'm speaking of the marijuana vote. And it could be up for grabs next year.

Being for marijuana reform has become an all-or-nothing thing these days. It used to be that the pro-reform people would eagerly accept tiny incremental changes. That is no longer true, because voters across America now have the examples of four states and the District of Columbia where recreational marijuana is legal for adults to use as they see fit. In none of these jurisdictions has the sky actually fallen, it now almost goes without saying. Much like the shift in the gay rights movement from demanding civil unions to accepting nothing less than full marriage equality, in 2016 the shift among pro-marijuana voters is also going to be profound, because legalization is now an achievable reality for them to fight for. Medical marijuana is a weak and unsatisfactory substitute nowadays, in other words.

Nobody yet knows how many states will have ballot initiatives in 2016 concerning marijuana. In some states, this might mean just allowing medicinal marijuana or decriminalization, but in a significant number it is going to mean the citizens will be voting on full recreational legalization for adults. There could be only a handful of such ballot initiatives, or the number could reach double digits. If even half of them pass, the legal landscape for marijuana reform is going to look a lot better.

Support for legalization has been rising, and is now reliably over 50 percent nationwide. The numbers break down to some extent along geographic and partisan lines (more Democrats and Independents are pro-reform than Republicans), but the most interesting thing is how the issue breaks down along age lines. Young voters are overwhelmingly for marijuana reform. The problem is, young voters are a pretty fickle bunch. When they get excited about an election, they can indeed turn out to vote in droves (Obama, 2008), but when they are not excited about an election, they can stay home (2014). For them, getting to vote for legalization on their ballot definitely qualifies as an excitement factor. But again, even the pro-marijuana vote is not entirely partisan. Barack Obama won Colorado when it voted for legalization, but the legalization measure got more votes than Obama did.

In some states, this likely won't matter much. California, for instance, is likely going to vote on legalization in 2016, but the state leans so far Democratic that its Electoral College vote is probably not ever going to be in question. But that's not true everywhere, and even in states where legalization (or even medical marijuana) is not on the ballot, some voters will be influenced by what stance politicians take on the issue. And a battleground state may become more competitive in the presidential race if it also has a legalization measure on the same ballot.

Chris Christie made news today for taking an uncompromisingly harsh stance on marijuana reform. He accurately pointed out that almost all the reforms achieved under the Obama administration are temporary and discretionary. As president, Christie has thrown a marker down that he would instead crack down on any state daring to defy federal law, and would not tolerate the situation as it now stands in Alaska, Colorado, Oregon, Washington, and D.C. It would be a massive reversal of the gains made at the Justice Department over all of Obama's term. The D.E.A. and federal prosecutors would be fully unleashed upon all the weed stores and dispensaries. Call it the "total war" position.

Now, Christie's not even officially in the 2016 presidential race. He may not even run. But if he does (and even if he doesn't, if the media picks up on the issue) he's staked out the most "law-and-order" position possible. The other Republicans will be confronted with this, and have to either offer support for Christie's position or explain what they'd do differently. As I said, it's not really all that partisan issue for many, and it certainly isn't a Tea Party issue (that I'm aware of), so the Republican candidates might feel freer to be more creative in the positions they take. Rand Paul may occupy the position ideologically farthest from Christie's, but that certainly doesn't preclude other Republicans from making a "states' rights" argument of their own. So far, not every Republican has taken a clear stand on the issues of medical marijuana and full legalization, so it'll be interesting to see the full spectrum of opinions from them.

It will also be interesting to watch Democratic politicians struggle with the issue. Most are quite likely going to attempt either some mealy-mouthed support or perhaps some vague and nebulous language. The Democratic Party as a whole may be awfully timid and offer no leadership at all on the issue. Democrats have an institutional memory of how effectively the whole "soft on crime" charge worked against them politically, back in the 1980s and 1990s. Democrats are now roughly in the position they were on gay marriage back in 2008 -- they knew which side of history was likely to be successful, but they were also terrified of political blowback for getting out in front of the issue too soon.

What will Hillary Clinton do on marijuana reform? This is an interesting question, one I have no real answer for yet. For that matter, I have no idea how bold or cautious a campaign she's going to run in general. If she chooses the overly-cautious route (in other words: "avoid offending anybody too much"), then I could easily see her retreating to, at best, halfhearted support. Clinton will likely be pinned down on the issue by having to answer whether she supports -- and would continue, as president -- the actions Barack Obama and Eric Holder have already taken towards ending the federal War On Weed. She may hedge support for full legalization with some version of the "let's let the states truly be laboratories of democracy, and let's see how the experiment works out" reasoning. Whether this will be good enough or not for the marijuana vote remains to be seen.

Marijuana voters, in the recent past, would have been overjoyed at hearing a candidate define the position that Barack Obama has taken: leave the states alone, let their experiments stand or fall on their own. But while that may have been enough previously, now the prospect of full legalization is a real possibility. To truly motivate the marijuana voter, nothing short of expressing support for state legalization and for perhaps descheduling marijuana and adding it to the Bureau of Alcohol, Tobacco, Firearms, and Explosives. In other words, ending the D.E.A.'s involvement entirely, and changing federal law to allow the states to do whatever their citizens want.

The marijuana vote can be highly motivated (my required pun for marijuana articles, I suppose...). By this, I mean a whole bunch of first-time voters can come out of the woodwork when marijuana is up for a vote. Many of these voters are otherwise politically apathetic, and regularly don't vote because they don't see any point in doing so. They are not ideologically set in concrete on other political issues -- marijuana reform truly does cut across many of the common demographic divides in American politics. But this cuts both ways, too. It is a "gateway" issue for many of these voters (especially the "single-issue" ones), and they will not vote for any politician -- of either party -- who doesn't champion the issue themselves.

This likely will only come into play if the Republican nominee is not following Chris Christie's lead, and instead expressing support for state experiments at the federal level. This could mean Rand Paul, or it could mean another Republican sounding reasonable on the issue (again, it fits into the conservative "states' rights" argument perfectly). This could pressure Hillary Clinton to clarify her position, and she'd have to choose between: rejecting Obama's approach and tacking closer to Christie, supporting Obama's approach but not advocating any further change, or wholeheartedly supporting ending the federal War On Weed. If she chooses the Christie route, it would mean she'd be to the right of the Republican nominee, an odd place for a Democrat to be. If she choose the middle route, there wouldn't be any significant difference between her and her Republican opponent. So the only way to really get out in front of the issue would be the last one -- actually addressing the ridiculousness of the Schedule I designation of marijuana in federal law.

If the prospect of the Republican being out in front of Hillary Clinton and the Democrats on the issue of federal marijuana reform seems farfetched, consider that even such staunch conservatives as Rick Perry have offered some support for filing marijuana under the "states' rights" label. In fact, the most likely outcome is where the two candidates don't radically differ on the issue, and both are generally supportive of the Obama "hands off" policy, while being more timid on changing federal law any time soon. But this may be the last election where politicians will be able to dodge the issue in such a fashion.

If five or six states successfully vote for full legalization in 2016, then the dam will have absolutely burst and we're never going back to the way things were, ever again. Either Hillary Clinton or some Republican president will have to adjust to the new reality of having 10 or more states openly defying federal law. That's going to require more than just what Obama and Holder have so far done. To put it another way, the issue may become unavoidable in the next president's first term in office.

Chris Christie has weighed in, so to speak. He's taken an absolutist position. It will be interesting to see how the other presidential aspirants now react. There is an emerging demographic on the American political scene. The marijuana vote is truly up for grabs. A lot of young people might just vote for a Rand Paul or another Republican who fights to be the most opposite from Christie's position. It's an opportunity for both the Republicans and the Democrats, depending on who decides to get out in front and show some real leadership on the issue.

-- Chris Weigant

Cross-posted at The Huffington Post

Follow Chris on Twitter: @ChrisWeigant