Glenn says that, apparently, the incoming Chief Justice thinks that there's nothing that the Commerce Clause doesn't prohibit. Sounds like it's time for a constitutional amendment.

It seems to me that Roberts is saying a new cloning technique would be open to federal regulation, and its hard to disagree with the idea that such a widely applicable technology would not be interstate and have a large number of effects, even if it was originally just used for our hapless arroyo toad, who lives just in California. In fact, from everthing else Roberts has said, he seems to interpret the Commerce clause quite narrowly, enough to worry many environmentalists.

What would it look like?

"Congress shall have no power to regulate interstate commerce accept in circumstances that actually involve interstate commerce, dammit!"

Or do you have a more cogent test in mind?

"Congress shall have the power to regulate the flow of money and goods crossing state lines." Doesn't cross the line, not in federal jurisdiction.

How's that?

Depends on how much we (pretend to) value federalism. I suggest that an amendment to the Constitution that did would look about like this:

"Section 1. The Congress of the United States shall have the power to veto laws and regulations of the several States that, in its opinion, restrict the flow of goods, money, people, and/or ideas between them.

"Section 2. The Supreme Court of the United States, and the inferior courts to the extent not prohibited by law, shall have the power to veto laws and regulations of the several States that, in its opinion, restrict the flow of goods, money, people, and/or ideas between them.

"Section 3. The Congress of the United States shall have no power, except as set forth in Section 1 of this Article, to regulate commerce between the several States."