I do agree with your thesis that social conservatives are more comfortable with big government. Obviously fiscal conservatives are in this game solely because they want a small government.
I believe there is a genuine libertarian movement, especially among young people in this country, that could have a major effect on future politics. Ron Paul has surged in this primary as compared to 4 years ago, doubling or tripling his votes. If a charismatic, Obama-like candidate eventually runs as a libertarian, either in or out of the Republican party, they will probably be able to win not too far into the future from now.
My biggest problem with the libertarian message is the focus on the federal government. It's extremely easy for them to say the federal government shouldn't do this and that, but it allows them to totally skate the issue of what the state government should do. "It should be up to the states" isn't much of a philosophy. And if they want the state government to do as little as they say they want the feds to do, then they're pretty much asking for anarchy and the law of the jungle.
Gay marriage is another. In order to make it illegal everywhere is the nation, you have to make it a federal law. After all, if it's left to the states, some of ‘em will probably legalize it (MA/CA/etc). And if it's a federal law... you need the necessary federal-controlled police force capable of arresting anyone that breaks it. For if the gays are married and no one is punished, what sort of law is it, then?
Flag burning, too. Banning evolution in schools. You name it.
Every social conservative issue almost always defaults straight to the Federal level. Social conservatives cannot countenance anyone not following their views.
And since, at the most primal level, government is just brute force... by taking all their issues straight to the highest level of government in the land, they are simply stating their willingness to apply force against anyone that disagrees.
That is a quintessentially statist point of view.
Whereas the small-government, non-statist views that law and government (ie: force) should only be made and used at the lowest level possible, recognizing that not everyone wishes to exist as they do. And as long as there is no harm affecting them at the individual level, there is no need to exert force.
Furthermore, as government is brute force, you have to pay for the necessary, authorized body to actually exert it. And the more laws you have, the more people you need to enforce them. Additionally, the more people you cover under those laws also increases the number of people needed to enforce them.
Which means that statists = high taxes. And thus, since social conservatives tend to be more comfortable in a statist role... they are directly responsible for higher taxes.
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I would say to anyone that's ever said, "There ought to be a law"...
..."Are you the one paying for it?"