Measuring libertarian ideology with party manifesto data

Libertarian ideology espouses a distinct political project which seeks to revolutionise the structures of the liberal democratic state. Surprisingly, this radical worldview does occasionally influence mainstream right-wing parties, and libertarian ideologues within their ranks have, at opportunistic moments, been able to encourage their desired policy change. But how can we measure these shifts in libertarian ideas within political parties? First, this study explains the design of a novel measure for libertarianism using the Manifesto Project Database. Second, it will apply this libertarian measure to the political parties of the United States and several European countries to test its face validity. Finally, the ‘crucial case’ of libertarian ideas within the UK Conservative Party will be assessed through the measure. This article finds that the libertarian scale provides a valid and utilitarian measure for libertarian ideology, which should prompt further research.