Why do we need ethics if we have laws?”

Note: In responding to your classmates posts, respond to both Parts I and II of their initial posts.)
Part I
The information that you will need for the first part of the discussion can be found in Case 6J, p. 76; Case 8, p. 140; and Case 5, p. 46 of Thinking Critically About Ethical Issues. For two of those cases (you pick), clearly identify what you take to be the parties and the moral issue(s) that are at stake in those cases.
Part II
In the very beginning of one of your textbooks book, Vincent Ruggiero responds to the question “Why do we need ethics if we have laws?” (Ruggiero 4) in a rather striking way by claiming, in effect, that ethics is required by the law because it underpins and informs our laws in some way. At one point Ruggiero goes so far as to assert that, “…law is not possible without ethics. The only way for a law to be enacted or repealed is for one or more people to make a decision about right and wrong” (Ruggiero 4). Ruggiero attempts to back up this claim by providing some examples that he sees as providing some clear evidence for his position, one concerns the creation of a law against sexual harassment and another concerns the repeal of the law of Prohibition. In this vein he writes, “The only rational basis for a law against sexual harassment is that the act is wrong” and he adds further, “The Eighteenth Amendment to the U.S. Constitution made Prohibition the law of the land—until the Twenty-first Amendment repealed it in the name of justice” (Ruggiero 4, italics are mine).
My question for you then, is “Do you agree with Ruggiero’s assessment of the intimate relationship between ethics and the law?” I intend this question in a general sense, but especially in regards the two examples he gives concerning the laws against sexual harassment and Prohibition. That is, can you think of any other (non-ethical) explanations for why we (now/no longer) have these particular laws? If so, what would those reasons be if not “ethical” ones? And furthermore, what might that mean for Ruggiero’s initial characterization of the relationship between ethics and the law in general?