The American Conservative has a terrific article by former Bush speechwriter Matthew Scully. Scully argues that conservatives should be opposed to factory farming and animal cruelty in general. While there is much in this article that I don't agree with, it provides an excellent framework for arguing about animal rights with conservatives on their terms. Here are some choice quotes:

If one is using the word "obligation" seriously, moreover, then there is no practical difference between an obligation on our end not to mistreat animals and an entitlement on their end not to be mistreated by us. Either way, we are required to do and not do the same things. And either way, somewhere down the logical line, the entitlement would have to arise from a recognition of the inherent dignity of a living creature. The moral standing of our fellow creatures may be humble, but it is absolute and not something within our power to confer or withhold. All creatures sing their Creator's praises, as this truth is variously expressed in the Bible, and are dear to Him for their own sakes.

and

Having conceded the crucial point that some animals rate our moral concern and legal protection, informed conscience turns naturally to other animals—creatures entirely comparable in their awareness, feeling, and capacity for suffering. A dog is not the moral equal of a human being, but a dog is definitely the moral equal of a pig, and it's only human caprice and economic convenience that say otherwise. We have the problem that these essentially similar creatures are treated in dramatically different ways, unjustified even by the very different purposes we have assigned to them. Our pets are accorded certain protections from cruelty, while the nameless creatures in our factory farms are hardly treated like animals at all. The challenge is one of consistency, of treating moral equals equally, and living according to fair and rational standards of conduct.

Scully also comes up with my favorite one-line response to my least favorite comment about vegetarianism:

When people say that they like their pork chops, veal, or foie gras just too much ever to give them up, reason hears in that the voice of gluttony, willfulness, or at best moral complaisance. What makes a human being human is precisely the ability to understand that the suffering of an animal is more important than the taste of a treat.

[via Treehugger]