Social conservatives and federalism

Huckabee, pretty typical of social conservatives, thinks that there is a "moral issue" exception in the United States Constitution that allows any issue to be federalized if it is more moral than political:

WALLACE: Now, Thompson and McCain both talk about leaving abortion and gay marriage to the states, the way, in the case of abortion, it was before Roe vs. Wade ever became the law of the land in the first place.
Why isn't that good enough, basically making this a federal issue and leaving it up to each state?

HUCKABEE: Well, it's the logic of the Civil War. If morality is the point here, and if it's right or wrong, not just a political question, then you can't have 50 different versions of what's right and what's wrong.
Again, that's what the whole Civil War was about. Can you have states saying slavery is OK, other states saying it's not?
If abortion is a moral issue â€" and for many of us it is, and I know for others it's not. So if you decide that it's just a political issue, then that's a perfectly acceptable, logical conclusion.
But for those of us for whom this is a moral question, you can't simply have 50 different versions of what's right.

Murder is a moral issue as well, and in many states it is not enforced consistently. Social conservatives should be equally worried about the fact that so many people are getting taken off of death row by the Innocence Project. There is no moral distinction between a system that is often systematically sloppy about handing out convictions that lead to the execution of innocent men and women, and one that allows private citizens to murder their unborn children. The distinction, if it exists, is purely one of emotion that comes from the fact that children are considered, as a group, considered more easily victimized than adults. In fact, there are so many "moral issues" with the way that the so-called "criminal justice system" handles things ranging from evidence discovery, to handing down sentences, that Bible-believing Christians ought to consider our system almost fundamentally broken from a moral point of view.

Yet, as is often the case, there are only a few areas where social conservatives (not all of whom are Bible-believing Christians, so don't think I'm conflating the two) consider there to be a moral case that is worth trashing the constitutional separations of power between the states and federal government. Right now, the only three major ones, in order, are abortion, homosexual marriage, and the drug prohibition (damn those pesky states that found it illogical to outlaw marijuana for terminal cancer patients, while doping them up on harsh, addicting, artificial opiates). All that results from these, in practice, is to end up empowering the federal government to provide the least desirable outcome for social conservatives. The simple fact is, social conservatives are living in the reality of the federal government usurping the states and deciding on the moral issue of abortion. That is precisely what Roe v. Wade is. There is little doubt in my minds that a future Supreme Court will rule homosexual marriage legal under the full faith and credit clause at some point in the next ten to twenty years, barring a constitutional amendment that unimpeachably declares against that sort of interpretation.

The "moral issue" argument is, ultimately, an appeal to emotion, not to reason. Anyone with a lick of sense can make a "moral issue" argument that, while mostly sophistry, is plausible enough to give it legs. In many jurisdictions, there are already enough laws against self-defense, gun ownership, property rights, among other things, to fit equivalent arguments to the one that "if even one state allows abortion, that is morally unacceptable." That, to me, is dangerous, and I say that any social conservative who says that abortion is a moral exception deserves to be called an idiot and a coward for refusing to face up to the obvious consequences of their distaste for strict constructionism.