The dissenting opinion on Obamacare ruling is hilarious

You may have read that the Appeals Court for the 11th Circuit ruled Obama's healthcare law was unconstitutional and that Congress exceeded its authority by mandating  Americans to purchase  expensive healthcare coverage. What you may not have noticed was the dissenting opinion from Judge Stanley Marcus. I'm not a Constitutional scholar, but this argument strikes me as... really crappy?This was in the article on the story over at Yahoo.com:

The majority "has ignored the undeniable fact that Congress' commerce power has grown exponentially over the past two centuries and is now generally accepted as having afforded Congress the authority to create rules regulating large areas of our national economy," Marcus wrote.

Is that how it works? The argument of  'they've been doing unconstitutional things for a very long time!' does not sound like an explanation of how the Constitution allows for something like a healthcare mandate. The administration says it fits under the Commerce Clause, but that gave Congress authority to regulate commerce, not force someone to buy stuff.

While the 'everybody's doing it' argument is totally rad, it's not based anything to do with the Constitution. If that's the administrations stance I can't imagine the Obamacare mandate survives.