In his Theory of Moral Sentiments, Adam Smith offers what strikes me as an extremely insightful discussion of the role of utilitarian arguments in moral thinking. I often find myself trying to remember or paraphrase this passage, so I finally hunted it down (a process made easier by the Liberty Fund search tool). It's at II. ii. 22-23:

Sometimes too we have occasion to defend the propriety of observing the general rules of justice by the consideration of their necessity to the support of society. We frequently hear the young and the licentious ridiculing the most sacred rules of morality, and professing, sometimes from the corruption, but more frequently from the vanity of their hearts, the most abominable maxims of conduct. Our indignation rouses, and we are eager to refute and expose such detestable principles. But though it is their intrinsic hatefulness and detestableness, which originally inflames us against them, we are unwilling to assign this as the sole reason why we condemn them, or to pretend that it is merely because we ourselves hate and detest them. The reason, we think, would not appear to be conclusive. Yet why should it not; if we hate and detest them because they are the natural and proper objects of hatred and detestation? But when we are asked why we should not act in such or such a manner, the very question seems to suppose that, to those who ask it, this manner of acting does not appear to be for its own sake the natural and proper object of those sentiments. We must show them, therefore, that it ought to be so for the sake of something else. Upon this account we generally cast about for other arguments, and the consideration which first occurs to us, is the disorder and confusion of society which would result from the universal prevalence of such practices. We seldom fail, therefore, to insist upon this topic.

But though it commonly requires no great discernment to see the destructive tendency of all licentious practices to the welfare of society, it is seldom this consideration which first animates us against them. All men, even the most stupid and unthinking, abhor fraud, perfidy, and injustice, and delight to see them punished. But few men have reflected upon the necessity of justice to the existence of society, how obvious soever that necessity may appear to be.