Hank - I'm afraid I'm with Sloth on this one. Any behavior at all can be rationalized (a la Stalin, Lex Luther, etc.). For religious people, moral values come from God, and we use our reason and intellect in putting those values into practice in (normally confusing) lives. Imagine a guy who can steal a diamond necklace, and knows that he can get away with it (i.e., no punishment in this world). If he believes in God, he knows what he is doing is wrong, and that God will be displeased, and that he will be distancing himself from God and from the chances for salvation (unless he's truly repentant). On the other hand, he may not believe in God and rationalize (using reason) that society would be worse off if everyone did that. In the interests of living in a society like he wants, he may still not take the necklace (like you, he uses his reason to posit what is right and wrong, AND he reasons as you do). Finally, a man who does not believe in God, and reasons that the best thing for him is to look out for number one may simply take the necklace (like you, he also uses his reason to posit what is right and wrong, but he starts with a different set of assumptions). There are many, many rational people who fall into the third camp. In the absence of God's morality, we may rationally make anything up at all. Same for Stalin. Same for Hitler. Same for Lex Luther. They were all rational men who made up their own versions of right and wrong.
But what about those instances where God has been shown to practice moral relativism?