Is a legislative purpose a license to judge the effectiveness of legislation?

[O]ur inquiry into legislative purpose is not intended as a license to judge the effectiveness of legislation. When considering the Fifth Amendment issues presented by Hawaii's Land Reform Act, we noted that the Act, "like any other, may not be successful in achieving its intended goals. But `whether in fact the provisions will accomplish the objectives is not the question: the [constitutional requirement ] is satisfied if... the... [State] Legislature rationally could have believed that the [Act] would promote its objective.' " Hawaii Housing Authority v. Midkiff, 467 U.S. 229, 242 (1984).