The point is that anytime a judge rules in contravention to the Constitution for whatever reason, he is violating his oath of office. You are simply stating that moral laws (however you might define that) are above the Constitution. People on the left believe the same thing. If a judicial nominee feels there would be times that he cannot in good conscience follow the Constitution, he has no business nor right to agree to serve. Either that or the words "So help me God" mean absolutely nothing to him.
Indeed, judges, and everyone else who comtemplates a position of power today should decide whether or not he should avoid any association with the secular state. This is the question Weyrich asked about a decade ago, and it is still without an aswer. In Europe in particular, it seems to me that it takes certain Quixotic quality for anyone to contemplate a career in anything to do with government.
Naturally, there is plenty an honest judge can do without ever coming in conflict between his oath of office and the moral law. 99% of the case load has nothing to do with the areas where the law has stepped outside of the moral perimeter. It would be a straw man for you, for example, to argue that a judge would then be permitted to interpret any law as he sees fit and claim adherence to moral law. In order to do so the judge must see a clear moral law imperative, and a clear man-made law mandate againt the imperative.
This having been said, it is a well-establishes tenet, particularly in America, that ultimately, morals trump the man-made law, even the constitutional law. In the past we saw it with slavery and Jim Crow laws. Today, we see it in abortion laws, and increasingly in various oppressive church-state relation laws, and, of course, gay "marriage". Those, in my humble opinion, should be ignored across the board by those who have the misfortune to serve in government or in the courtroom, here or in Europe, and the effects of these laws should be peacefully resisted by everyone as a matter of Christian duty and civic duty.