But Johnson will sound to many like a one-issue candidate, because there's one issue that sticks out, above all else, in his platform: Johnson wants to legalize marijuana. And he's eager to tell you about it.

I've seen Johnson's stump speech in person, and it works like this. He introduces himself as an entrepreneur who has applied business experience to government. He talks about his record of vetoing 750 bills from New Mexico's Democratic legislature, during his two terms, to keep spending in check. Then he jumps right into marijuana.

On that topic, the former governor articulates his views persuasively as a fiscal hawk, arguing that government can't really afford to incarcerate so many drug convicts. "We're arresting 1.8 million people per year," Johnson told the crowd at the Conservative Political Action Conference (CPAC) in Washington, D.C. in February. "We now have 2.3 million people behind bars in this country, we now have the highest incarceration rate in the world." The crowd was receptive.

This is how Johnson explained his views on marijuana legalization to me in an interview in January, before he spoke to a small group of students at American University, one of many colleges he visited in the past year.

My reasons for doing it are A through Z, but initially it was the fact that I had promised a cost/benefit analysis to everything it was that state government was doing. Well, it turns out that half of what we spend on law enforcement, the courts and the prisons, is drug related, and to what end? Now this is where I came from it initially, and I have smoked marijuana in my life also, so I've never really thought it criminal -- I've never really thought it warranted jail sentences. But as governor of New Mexico, half of law enforcement, courts, prisons -- drug related. And what are we getting for spending all that money? Well, we're arresting 1.8 million people a year in this country and we now have 2.3 million people behind bars, which is the highest incarceration rate of any country in the world, so after looking at the issue for a fairly short amount of time, I just came to the overwhelming conclusion that 90 percent of the drug problem is prohibition related, not use related. That's not to discount the problems of use and abuse, but that ought to be the focus. So legalize marjiuana, control it, regulate it, tax it, never gonna be legal to smoke pot, become impaired, and get behind the wheel of a car and do harm to others, never gonna be legal for kids to smoke pot, or buy pot. And under which scenario would pot be more available, the one that exists today where you can virtually buy it anywhere and the person that sells pot also sells other drugs, or a situation where you had to produce an ID in a controlled [setting] like alcohol to buy pot? Based on Holland's experience and Portugal's experience, I think you could make a case that there would be less kids smoking pot than there is today.

This plan to legalize marijuana seems to be an extension of Johnsons' thoroughgoing libertarianism, but given that he makes it a prominent component of his platform, Johnsons' palatability to GOP voters will hinge on their acceptance of his point. And that's not likely to happen in the next year and a half.