It's hard to believe that at one time last year we had approximately two-dozen contenders ready and raring to become the 45th President of the United States. However, with most primaries and caucuses in the rearview mirror, two likely nominees have emerged.

On the Republican side, Donald Trump is the last man standing, with rivals Ted Cruz and John Kasich suspending their campaigns. Without any major opposition, Trump should be able to net the votes and delegates needed to secure the GOP's nomination for the November ballot. For the time being, he's being referred to as the party's "presumptive nominee."

For the Democratic Party, things may not be 100% certain, but it's looking very likely that Hillary Clinton will be her party's nominee come November. Considering the way the Democratic Party assigns delegates and superdelegates, Clinton could hit the magic number needed to secure her party's nomination by June 7, the date of the California primary.

With the field having been whittled down to an (un)likely showdown between Trump and Clinton, the process of contrasting the two to see which would be better for America as a whole can begin. Voters typically do this by analyzing the two candidates' stances on an issue-by-issue basis. As expected, Social Security, national security, jobs growth, and our national debt are all issues that will be at the forefront of the presidential debates.

A surprisingly popular issue this election season

But a surprising issue has worked its way into the mix this presidential election that's never before been such an important issue for Americans: the potential legalization of marijuana.

According to an October 2015 poll from national pollster Gallup, 58% of respondents were in favor of fully legalizing marijuana. Despite this record-tying number (a previous year Gallup poll also showed 58% support for full legalization), neither Trump nor Clinton, or any other candidate save for perhaps Democratic Party contender Bernie Sanders, has been remotely ready to put forth legislation that would legalize the use of recreational marijuana.

Of course, this hasn't stopped four states (Washington, Colorado, Oregon, and Alaska) from legalizing the sale of adult-use marijuana and regulating the substance, all while the federal government stands firm by the drug's schedule 1 status (i.e., illicit). In fact, with the help of nearly $588 million in recreational cannabis sales in 2015, Colorado narrowly missed $1 billion in cumulative legal pot industry sales last year.

84% of the public supports this, and so does "The Donald"

However, the marijuana industry doesn't need full legalization of the drug to necessarily be successful. Every new approval, be it recreational marijuana or medical marijuana, is a step in the right direction. With Pennsylvania's legislature approving a medical marijuana bill last month, there are now two dozen states that have approved the use of pot for medicinal purposes.

The truly interesting thing about medical marijuana is that its approval rating is truly through the roof among the American public. A survey conducted in April 2015 by CBS News found that 84% of respondents would be in favor of seeing marijuana legalized for medical purposes in the United States. Legalizing medical marijuana could provide new treatment options for patients with certain types of epilepsy, glaucoma, and terminal cancers, and it could be an instant tax revenue generator for states and even the federal government (though recreational marijuana sales would probably be considerably larger than medical marijuana sales in the U.S.).

In spite of this overwhelming support in favor of medical marijuana's legalization, the federal government, and the vast majority of the original presidential candidates, either have no desire to legalize its medical use, or they'd rather wait for additional safety data to become available. Hillary Clinton is one such candidate. With the exception of extreme cases of need or compassionate use, Clinton would restrict access to medical marijuana. She doesn't have an issue with the current status quo of allowing states to legalize and regulate marijuana on their own, but she has clear concerns about its safety profile for the time being.

On the other hand, in an interview with Fox News, Donald Trump stated that he was "a hundred percent" in favor of the legalization of medical marijuana. The jury was still out on recreational marijuana for Trump, who prefers a wait-and-see approach, but his clear support for reforming the federal view on medical marijuana is a clear departure from the thinking throughout Capitol Hill.

Depending on who gets into the Oval Office, we could see a major shake-up in the marijuana industry come 2017.

Marijuana is growing by leaps and bounds, but is still a risky investment

But even if Clinton becomes our next president, estimates suggest the marijuana industry will continue to expand. According to ArcView Market Research, the marijuana industry, through state level recreational and medical expansion, is expected to grow by 30% annually through 2020. This would suggest a market value of $22 billion for the industry by 2020, compared to $5.4 billion in 2015. The industry is expected to create plenty of jobs (and not just retail jobs), and it's clearly drawing a lot of interest from investors.

Yet investors would be wise to realize that rapid growth doesn't necessarily translate into success for larger-scale marijuana companies. Because the federal laws governing marijuana are so restrictive, marijuana businesses aren't allowed to take normal tax deductions, and they have minimal or no access to basic banking services like checking accounts or lines of credit. As long as these disadvantages remain in place, expansion and hiring could be challenging, which will likely have a direct impact on profitability.

My suggestion as an investor? Wait to see how the November elections play out. We have numerous states voting on whether to legalize medical or recreational marijuana, and we have two candidates with very different views on medical marijuana vying for the Oval Office. After the election we should have a clearer picture on the marijuana industry's path going forward. Until then, it's really a guessing game -- and I much prefer not to jump to conclusions with my hard-earned money.