Eugene Volokh has a brief but sensible essay about the "forcing moral views" meme.
All of us draw lines in this field, whether at conception, viability, birth, or whenever else. None of us can prove the validity of those lines through science or through abstract logic.
Those of us (like me) who draw secular lines shouldn't feel superior to those who draw religious lines here -- and we certainly shouldn't think that the Constitution or political morality somehow makes our linedrawing more proper. We can and should debate, as best we can, where the lines should be drawn, but we should recognize that at some point it comes down to the unproven and unprovable, for the secular among us as well as for the religious. And we should realize that no attempt to protect children from killing -- wherever you draw the line about what constitutes a "child" -- can operate without forcing one's moral views on others.
Good point: resorting to the "you want to force your moral values on me" argument is lazy. If you want to draw the line on a moral issue at a different place than your opponent, then argue for doing that directly. I wonder (however) if lines cannot be drawn in a rational place on these issues; is it really down to the "unproven and unprovable" in all cases, as Professor Volokh asserts? I'd like to think not.
I like the idea of treating religious moral views with toleration and respect. But even as I type that, I think of bluenoses and censors and I desperately want to add the caveat: just not all of them.
But where to draw the line there?
This seems to be the theme of the day, because Edward Feser makes a similar point in his essay at Tech Central Station:
Not all moral principles ought to be enforced by the power of government, but almost everything government does is based on some moral principle or other. It is fatuous, then, to hold that "we shouldn't legislate morality," if this means that controversial moral principles shouldn't guide public policy. And almost every moral principle is controversial to a significant extent: even when people agree that murder is wrong, they often disagree about what counts as murder, as the disputes over abortion, euthanasia, and even the killing of animals attest. The question, then, is not whether controversial moral principles ought to inform our laws, but rather which controversial moral principles -- liberal, conservative, libertarian, or whatever -- ought to inform them. As the Schiavo case illustrates, it is inevitably going to be extremely difficult, if not impossible, to settle these matters in a way that is going to satisfy all members of a pluralistic society. But it is no use pretending that the difficulty doesn't exist -- or that it is only conservative moral scruples that give rise to it.
Fine distinction, but (again) little guidance for the confused folks (like me) who think it's fine to "legislate morality" for things like (say) banning infanticide, but not for (say) charity or "substance" use.
And I swear I read something else on this topic earlier, but for the life of me, I can't find it now. Oh, well, possible update later …