Rand Paul isn't Libertarian. Here's how we know:

7/07/2015 07:22:00 AM
Any analysis of political ideologies is going to produce some version of this chart:
Political ideologies are spanned by two basic dimensions: economic freedoms versus social freedoms. Source.
Basically, ideologies can be measured in terms of what they define as freedom: Republicans and conservatives generally define freedom in terms of economic freedom, and don't have a problem with regulating what people can do outside the marketplace. Democrats and liberals define freedom in terms of the freedom to do whatever you want outside the marketplace, but don't have a problem regulating how people must conduct business inside the marketplace. Libertarians are defined by the fact they value both equally: freedom includes both the ability to do what you want outside the marketplace and inside it. The fourth box is labeled "hardhats," a term that comes from Paul Krugman, but there's really no one in that box because the only way to get there is to not value any kind of freedom at all--not a popular stance.

Andrew Kaczynski points us to this quote from Rand Paul that makes his ideology quite clear:
"if we tax you at 100% then you’ve got zero percent liberty. If we tax you at 50% you are half slave, half free."
Thus, Rand Paul places zero weight on non-economic freedoms, and highly values economic freedoms. That puts him squarely in the Republican/conservative box.

The absolutism of Rand Paul's conservatism is quite remarkable. Consider the hypothetical scenario where the government taxes 100 percent of income but provides free food and other consumption for everyone (nevermind how they pay for it, for the moment). Obviously, there'd be no point to working, and you'd have no freedom to increase your consumption beyond what the government hands out. There's no doubt that the high tax rate would reduce your freedom. But you certainly could enjoy quite a bit of other kinds of freedom in this world--just to take a timely example, you could marry whoever you want, of either gender. Rand Paul's position, then, is that the freedom to marry is insignificant compared to the ability to earn untaxed income. That's pretty solid Republicanism, which has no problem prescribing who people can marry and when they can get divorced, so long as taxes are low.

Incidentally, on Twitter I recently started a debate on a related question and Adam Omizek said this:And he's right: the lack of a paycheck is not what defines slavery. To put it differently, merely giving a slave a paycheck does not set him free--in fact, many slave owners did give them paychecks. Clearly, an integral part of the definition of slavery is it's involuntary nature--the compulsory labor and the lack of agency over one's own life. But according to Rand Paul, the inability to work for pay is the same as being forced to work for no pay.