Interestingly enough, abortion is one area in which natural-law conservatives think their approach to judging would give them some purchase. If one subscribes to the view that the Declaration of Independence, with its attribution of political rights to a Creator, is a controlling legal precedent, one consequence (if one assumes that fetuses are persons, a big if) might be the judicial evaluation of pro-choice legislation. If that seems outrageous, natural-law types would argue, then so was the Supreme Court's 1967 ruling outlawing laws against interracial marriage, a ruling they say cannot be justified on positivist grounds. They have a point—but that point may just be that liberals and conservatives have a weakness for results-driven jurisprudence.
Is Scalia susceptible to that temptation where the Ten Commandments are concerned? That might be one way to interpret his aggressive unmasking of the "secular" rationale for displaying the commandments and his repeated references during oral arguments to the notion that laws come from God. Perhaps on this one issue he was offering a judicially significant nod to the natural-law lobby. Or maybe he was just venting the religious views that, however regretfully, he can't allow into the positivist cathedral of his legal method.