Frank Beckwith links to a talk by Christopher Wolfe on whether one can or should legislate morality. Wolfe is a great political philosopher and constitutional scholar who used to teach at Marquette University. He is now working for Thomas International. One of his projects is the establishment of a liberal arts university with a Thomistic focus.
Wolfe's Thomistic two-pronged argument is based on the link between legislation and the cultivation of virtue. Sure, we can't actually legislate morality, but we can and should use legislation to creates an atmosphere that directly or indirectly assists citizens to cultivate virtues (or at least minimizes their opportunity to cultivate vices).
One other point needs to be made about "legislating morality." Wolfe doesn't emphasize it (because his focus is different), but I'm sure he would agree. One of the most important reasons for outlawing evil human acts like abortion is that they are evil, no matter what the subjective culpability of the person seeking or performing an abortion is. I intend to come back to this in a later post. Abortion is a serious evil that a just society needs to prevent. There are two reasons it is seriously evil (in Catholic moral discourse, a "grave matter"): it takes innocent human lives and it drives a wedge between mother and child. The law of the land should outlaw abortion, whether citizens become more moral because of the law or not.