The Reason-Rupe September 2012 poll includes our favorite ideological questions to differentiate libertarians from liberals and conservatives. Using three questions, we can define libertarians as respondents who believe “the less government the better,” who prefer the “free market” to handle problems, and who want government to “favor no particular set of values.” These fiscally conservative, socially liberal voters represent 20% of the public in the Reason-Rupe poll, in line with previous estimates.

Among these likely libertarian voters, the presidential horserace currently stands:

Romney 77%
Obama 20%
Other 3% …

One other interesting data point from the Reason-Rupe poll. We’ve previously noted libertarians’ penchant to support third party candidates. For instance, 17 percent of libertarians supported John Anderson in 1980 and 33 percent supported Perot in 1996. What happens if you ask libertarians their vote preference and include Libertarian candidate Gary Johnson among the choices?

Romney 70%
Obama 13%
Johnson 14%
Other 3%