Apologies for all the commerce clause stuff today, but Judge Roger Vinson cited this really well-done video by Reason outlining the long-standing libertarian beef against expansive interpretations of the Commerce Clause:
Now, libertarians have been coming after Wickard for decades. But as the video explains, "from 1937 to 1995, not a single piece of legislation was struck down as exceeding the limits of the Commerce Clause," when U.S. v. Lopez struck down federal gun regulations. Then Gonzales v. Raich, was decided, and Justice Antonin Scalia wrote that "where Congress has the authority to enact a regulation of interstate commerce, it possesses every power needed to make that regulation effective," a broad interpretation of the commerce clause that is presumably valid because it was regulating marijuana-smoking hippies rather than ensuring health-care coverage.
I think the libertarian argument about the commerce clause being limited to the trade of goods and commodities is selective of history (and unlike those made by conservatives, consistent), but I understand why it's persuasive. I just want to propose an observation here: Libertarian arguments about the limits of the commerce clause are successful when they mesh with the preferred policy outcomes of conservative Republicans. That's why defenders of the ACA should be worried.