In an article that otherwise makes some good points about conservatives’ “populist” defense of junk food, Rod Dreher just can’t resist taking a swipe at a time-honored liberal strawman:

For conservatives, it may be revealing to compare the defensiveness with which many of us discuss what we do in the dining room to the defensiveness liberals approach discussion of what they do in the bedroom. Liberals, to overgeneralize, believe that what consenting adults do in bed with their bodies is immune from moral judgment. Social conservatives recognize the falsity of this view, understanding that immoderation in sexual matters corrupts individual character and can have deleterious social consequences.

I can see why this neat bit of parallelism may have been too tempting to leave on the editing-room floor, but it just doesn’t wash. A more accurate approximation to the “liberal” view would be that what consenting adults do in the bedroom is not a fit matter for state regulation. But liberals are hardly barred from making moral judgments about sexual relations. This is because consent is a necessary, but not sufficient, criterion for morally appropriate sexual acts. A liberal can easily say, for instance, that a relationship of equality and mutuality is morally superior to one based on humiliation and degradation, even if all the parties involved consent to their treatment.

Dreher here makes the common conservative mistake of assuming that because liberals object to some longstanding moral prohibitions (on, say, homosexual relationships) that they must object to all moral judgment in matters of sex. This only follows if you treat sexual ethics as a seamless whole that can’t be altered without the whole thing unraveling. But liberals typically take a different approach: they look for the deeper, underlying principles that justify a particular sexual ethic and try to prune off the bits that seem inconsistent with those principles, understood in light of changing social contexts and new knowledge. Thomas Aquinas and Immanuel Kant made some particular judgments about sex that nearly all of us (conservative and liberal) would now reject, but we can still use the principles of human flourishing or respect for persons to articulate a consistent sexual ethic.