I am a coward when it comes to making predictions about political events. Being a denizen of the internet, I have seen too many overly-confident netizens extrapolate the current hot story in the news cycle into a prediction about "inevitable" political outcomes. So it has taken me until past the half way point of this year's primary race to get around to making a pretty basic assertion: Ron Paul won't be president.
Ron Paul is having a pretty good year. One-fifth of the caucus vote and one-tenth of the primary vote is currently his, which is a little less than double what he did in 2008. But he still hasn't won a state this year. Some of his best states have voted, and he hasn't won any states yet. There is still a chance that he might pull out a win this year, but getting first in, say, Rhode Island or Montana is not exactly a ringing endorsement.
Anything is possible, so it is still possible that Paul can't win an election this year, or in 2016, or in 2020...although he is getting pretty old. But it is unlikely enough that we can practically say it is impossible.
So why can't Paul win? Is it because he is too old or has other personality traits that disqualify him? While perceptions of him might be a factor, they aren't the deciding one. Is it because of the lingering scandal over newsletters he may or may not have authorized with inflammatory, racist statements? It certainly hasn't helped him, but the electorate can be forgiving on events that happened twenty years ago. Is it because his ideology is too extreme? Getting close, but not quite there! Is it for the simple reason that he is only a Representative, which is not usually a springboard to the Presidency? This is closer!
The simple reason that Ron Paul can't win the presidency, and is having difficulty even in the nomination contest, is that Paul has no coalition. While his supporters are motivated, his campaign seems to be focused on turning out those supporters, instead of convincing people who do not share his entire ideological viewpoint. It isn't that his ideology is necessarily beyond the approval of the electorate, but the narrowness with which he tailors that ideology is.
Getting elected in the United States requires a coalition. Coalitions can be looked at in many ways: regionally, politically, demographically. But in any case, a coalition consists of different groups who have enough in common to set forth an agenda. The libertarian-leaning group of people that support Ron Paul are a single element, and have not had any success in having other like-minded people coalesce around them. Without a coalition, Paul can't win a single state primary, let alone winning a nomination or a race for the Presidency.
This is not to say that libertarians, or libertarian-leaning candidates, will be unable to ever run a serious candidacy, but when they do, they will have to build a coalition. And doing such a thing won't be too hard. What such a candidate (who very well could be Ron Paul's son, Rand Paul) would have to do is show how libertarian goals mesh with the interests of people who are not ideologically committed libertarians. Libertarians already believe that drug laws are outside of the rightful scope of government. But if you had a libertarian Governor who could point out that by not focusing on "victimless crime" he had managed to devote resources to fighting violent crime, you would interest not only ideologues, but pragmatists. If the same governor cut spending, he could trumpet it as "fiscal responsibility", which would be attractive to many voters. And if he cut truly unnecessary regulations and eliminated bureaucratic layers, that would appeal to many people.
In other words, there are many ways that a libertarian-leaning candidate could build up a coalition of support beyond their ideological true believers, by pointing out how libertarian positions could benefit the average person. But as of yet, they have not done so, and the current standard bearer- Ron Paul- seems to be unable to move out of his pocket, despite advances.
If I can finish this so-far straightforward political commentary with some armchair psychology, my own experience is that a large section of the libertarian community doesn't want to make these connections, and in a way, doesn't want to win. Much of the appeal of libertarian ideology seems to be about asserting personal autonomy, rather than actual results. The idea of personal autonomy is advanced whether or not political power is gained. So in large part, Ron Paul (or another such candidate) can't win the Presidency because such a victory is unnecessary for what their constituents actually want.