The Preposterousness of the Commerce Clause

Julian Sanchez comments on people calling Hudson's interpretation of the commerce clause "preposterous":

And the weird thing is, he's right... sort of! It does seem like a surprising result, given the last century of Commerce Clause precedent, that anything plausibly describable as economic activity might be found beyond the power of Congress to micromanage. "Preposterous on its face," even.  

But isn't it preposterous that it's preposterous? Step back from that steady accretion of precedents and instead just ask how far a federal power to "regulate commerce...among the several states"--especially in the context of separate and parallel powers to regulate commerce with foreign nations and Indian tribes--can plausibly be stretched. Isn't it the idea that "regulate commerce" could entail a power to require a private individual in a single state to buy health insurance that ought to seem kind of crazy? Shouldn't we find it more intuitively preposterous that a provision designed for tariffs and shipping rules should be the thin end of the wedge for a national health care policy? 

And yet it isn't! It's the denial of that infinitely flexible reading that now seems strange. And that's really strange.

Obviously, I agree with Julian.  I have been reading a lot of well-meaning liberals who are befuddled by the notion that conservatives are going after the mandate, when that runs the risk of bringing on single payer.  Personally, I kind of doubt that, but this is completely beside the point.  On a reading of the commerce clause that allows the government to force you to buy insurance from a private company, what can't the government force you to do? 

This doesn't seem to be a question that interests progressives; they just aren't very excited about economic liberty beyond maybe the freedom to operate a food truck.  And so they seem genuinely bewildered by a reading of the commerce clause that narrows its scope, or an attempt to overturn the mandate even though this might lead us into a single payer system.  If you view this solely as tactical maneuvering, perhaps it really is preposterous.

And of course, for some conservatives, these operations are tactical, but for a lot, it's an actual horror at the ever-expanding assertion of government powers.  I'd like it if they'd get equally horrified about, say, the TSA and the drug laws, but there you are: neither side is as consistently supportive of liberty as I'd like.