Fr. Mitch Pacwa, S.J., answered a tough question on Threshold of Hope this week. Paraphrased, the question was: "Is the moral law which differentiates good from evil something that God dictates (and therefore what is good is good because He says so), or is God good because He conforms to this moral law (which therefore exists outside and before Him)?" In other words, is the moral law arbitrary because God invented it or is God subject to it because it was not created by Him?
I'll post his answer here later, but until then, does anyone want to try and give an answer? (Hint: think tertium quid.)