We overtly contribute our core beliefs to the likes of John Locke in which reason is not looked at in the same dispassionate wayas Descartes or especially Kant would see it.

 Indeed the Anglo-American general political philosophy as well as it's view of human nature has lead to Utilitarianism and John Dewey's Pragmatism.  It can be best described by that revered American Philosopher, Jiminy Cricket, who is quoted to have said, "Always let your conscience be your guide."

It's based on a philosophy that Human Nature is inherently good, where feelings and reason merge into Conscience and Common Sense.  That's not the Spockian philosophy Lakoff eludes too at all.

It's really the Repuclicans who are the Cartesians, actually Neo-Platonists.  They see themselves as the guardians of pure reason.

Their problem is that they think human nature is inherently Evil and the function of Government is to control the rabble.  Reason is the province of an ELITE.

The Rabble are unreasonable, so there is no point in reasoning to them.  They are governed by irrational feelings, which they see Liberals as using to win over the masses! I've seen many a Con post about how Spock-like they are and how Liberals vote on their "FEEE-WINGS!!!" You look at Ayn Rand's Objectivism, something Cons and Libertarians like to throw around at parties and that's about the closest thing to Spockism out there.

It's not their understanding of Reason that have Republicans playing the politics they do.  It's their complete LACK of understanding!  They think that Reason is the province of the Elite.  More irrationally they think the mark of true reason is to THINK LIKE THEM.  Like the great American Sage Ann Coulter says, "If Democrats Had Any Brains, They'd Be Republicans."

It's their view of the world consisting of Vulcans and Troglodytes, that makes them speak down to the American people, hide their real agendas and reasoning and use lowest-common denominator gimmicks. To market Conservatism as a life-style choice, rather than a political one.  (That's why they love Red/Blue America.)

That wasn't the way the Conservatives used to be.  Classic Conservatives like Barry Goldwater believed in the Goodness of the People and thought Government interfered with individual freedom.

But Goldwater got his ASS kicked, so over time Cons lost their faith in the American public.  And they stopped reasoning with people.