Constitutional or Not?

Steve Chapman writes about whether current health care legislation is constitutional or not. From the article:

“Never in the history of the United States has the federal government ever required someone to engage in an economic activity with a private party,” Georgetown University law professor Randy Barnett has said. If the Supreme Court goes along, he said, “there’s pretty much nothing Congress can’t do.”

George Will offers his thoughts here.

The only argument I've heard so far is the ICC, but I think that is a major stretch.