The culture is largely agricultural, with a strong tradition of hunting and firearms ownership. It would be rare to find an adult male who does not own a shotgun, a deer rifle and a hand gun. Indeed, it would probably be unusual to find a male child over twelve who does not own a .22 rifle. County Sheriffs will issue concealed-carry permits to virtually anyone, with a minimum of administrative hassle. There is no state income tax.
Casino gambling is legal.
Clearly, South Dakota is a very libertarian place, particularly when compared to the megalopoli of the East and West. What's hampered Libertarian candidates in the past is lack of necessary support. Freed from the necessity of actively campaigning for a Presidential candidate in 2004, the National Party would have the means to generate more campaign money than a Democrat or Republican candidate would ordinarily need to get elected in South Dakota. A couple of million bucks is alll it should take. This is an attainable goal in a small population state.