This is a for real inquiry for non-lawyers, but will require a tad of political perspective.
Hobbs said we make laws to keep from killing one another, for safety's sake.
Locke said we make laws to keep from stealing one another's property--to protect our incohate property rights.
Aristotle said, well I'm not sure I could possibly know, but I think that it had something to do with pursuing the GOOD, whatever that means.
Anyway, under what theory do we prosecute Michael Vick? The constitution guarantees us the right to life, liberty and property. Which of those does the federal criminal law against cruelty to dogs further.
Alas, it is from the commerce clause that the right of the sovereign to regulate in this area arises. The commerce clause is used to protect the moral high ground? One would have hoped that the laws against cruelty to animals stood on higher ground, on, for example, Aristotlean notions of the Good, that which has a baring on achieving the highest in human endeavors. But no, we are relegated to the squiggley little commerce clause to search for the justification of this law.
I, for one, find it hard to believe that our founding fathers saw in this commerce clause the power of the Sovereign to restrict a man's freedom to treat any animal that he owned fair and square exactly as he wished. Am I alone in this, or do you guys see it otherwise.
I can't believe that I sound like a Libertarian here, or worse still a Republican.