In this video Josh Blackman discusses his new book, Unprecedented: The Constitutional Challenge to Obamacare. I was the commentator, and our conversation turned to the role of popular constitutionalism in the Obamacare challenge. Among other things, we discussed how the arguments against the individual mandate moved from "off the wall" to "on the wall," and the role played by political parties, political elites, legal intellectuals, and the media.