Federalist trickery

The NYU Federalist Society had Randy Barnett come to speak today, and I went. He's a really engaging speaker. Since I followed the news around the time of Raich really carefully, I had heard a lot of the story's before, including the great one about how Justice Stevens temporarily forgot supply and demand curves during oral argument. One of the new anecdotes I picked up was that his argument against the substitution effect came from Charles Fried during the moot court of the case at Harvard. For those of you who weren't following Raich as closely, the argument goes like this:

Government: Congress has the power to regulate the use of medical marijuana under the commerce clause.
Barnett: But my clients don't actually engage in commerce, one of them grows their own marijuana and the other receives it for free from two people who grow for her.
G: But if they didn't get it for free, they'd be buying on the market. Hence, there is a substitution effect between their activity and market activity.
B: By the logic of that argument, there is no distinction between economic and non-economic activity. For instance, marital sex is a substitute for purchasing sex. Therefore, Congress can regulate marital sex under the Commerce clause power.

The other good story he told was about how he decided to become a 9th Amendment expert after he quit being a prosecutor. He said he got everything that had been written on the 9th Amendment, piled it up on his desk, and it wasn't too thick. So he realized he would be one of the nation's foremost experts (at one point he called himself the foremost expert, but then took it back) if he read all of that. And he did. And then I found twenty dollars.