Stephen Breyer in The Los Angeles Times

On Health Care: Broad authority for interstate commerce, like ObamaCare

The Constitution not only gives Congress the power to regulate interstate commerce, but the authority to enact all laws that are "necessary and proper" to carrying out this authority. The "choice of means" for carrying out its aims is left "primarily to the judgment of Congress," said Justice Breyer in US vs. Comstock. If Congress has a delegated power, such as over interstate commerce, it may regulate it in a way that infringes on the state's authority.