In a recent article on TheBlaze, Reason’s Matt Welch, FreedomWork’s Matt Kibbe, and David Boaz, speculated whether Romney can win over libertarians. As we’ve shown in previous studies, libertarians represent a key swing vote that decides elections.

Well, Emily Ekins and our friends at Reason shared with us data from a recent Reason-Rupe poll by which we can measure the libertarian vote. This is the best data point yet on where libertarians stand in the 2012 election.

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%

Romney’s share of the libertarian vote represents a high water mark for Republican presidential candidates in recent elections.

As the chart below shows, George W. Bush won 72 percent of libertarians in 2000, but lost many libertarians by 2004, as the wars, spending, and growth of government weighed on many libertarians. John McCain matched Bush’s 2000 vote share, winning 71 percent. Many libertarians seem to have preferred McCain’s independent streak to Obama’s soaring promises. But if the election were held today, the Romney/Ryan ticket would get more libertarian votes than any candidate since 1980.

Romney’s vote share may be more a libertarian vote against Obama than for Romney. Few libertarians were excited about Romney in the Republican primary. Indeed, Romney’s deficit among libertarian voters may well have been part of the campaign’s strategic calculation of adding Paul Ryan to the ticket. If so, it seems to be working.

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%

Of course, Gary Johnson has an uphill battle to be even listed among the top-tier candidates. But media stories have nonetheless asked whether Johnson will play the role of a “spoiler,” drawing enough libertarian votes from Romney to hand the election to Obama. The data show this to be unlikely. When Johnson is listed, he pulls votes equally from Romney and Obama, drawing 7 percentage points from each. Adding Johnson to the mix is a wash for Romney, at least among libertarian voters nationally.

See more analysis on the Reason-Rupe poll here. And keep an eye out for our upcoming e-Book, The Libertarian Vote: Swing Voters, Tea Partiers, and the Fiscally Conservative, Socially Liberal Center.