http://en.wikipedia.org/wiki/Commerce_Clause
United States Constitution (Article 1, Section 8, Clause 3)
"[The Congress shall have power] To regulate commerce with foreign nations, and among the several states, and with the Indian tribes;"
http://en.wikipedia.org/wiki/Commerce_Clause
The executive and congressional branches with the complicity of the judicial branch have abused the hell out of this clause to authorize regulation of almost every aspect of our society, ever since Wickard v. Filburn in 1942. If you think about it, you can make a link, however tenuous, to ANYTHING that you want to regulate. If X affects Y, and Y affects Z, and Z affects Q, and Q affects interstate commerce, than Congress has the authority to regulate X. Ridiculous.
In short, this is nothing new, but that doesn't make it right. Unfortunately, the genie's out of the bottle now, and until there's a revolution, this situation will not change.