From Reason.tv, a really good introduction to the Commerce Clause, and the controversy around the constitutionality of ObamaCare.
Note the tautology the pro-congressional powers professor uses at the end: The Constitution only protects us from acts that are unconstitutional. He's being disingenuous: he's trying to say (without saying it outright,) that Congress should not have any limits on its legislative jurisdiction. Except we have a federal system, not a centralized system, for a very good reason. It's one of the things the founding fathers did to protect us from tyranny, and is so well documented that absolutely anyone who paid attention during their high school history class knows it to be settled fact.