Can moral flaws lessen an artwork's aesthetic value? Answering yes to this question requires both that artworks can be morally flawed and that moral flaws within a work of art can have an aesthetic impact. For present purposes, the author will assume that artworks can be morally flawed by such means as endorsing immoral perspectives, culpably encouraging responses that could harm oneself or others, or culpably encouraging responses that are wrong to have. Assuming that artworks can be ethically flawed, the author's goal in this article is to provide support for the claim that moral flaws can be detrimental to an artwork's aesthetic value. He will refer to the position supporting this claim as "moralism about art." In this article, the author presents a simple and straightforward argument: Moral flaws can become aesthetic flaws when they defeat the operation of good-making aesthetic properties. He offers new support for an old, but nonetheless contentious, position--moralism about art--based on the two leading theories of aesthetic properties. (Contains 43 notes.)