CHIEF JUSTICE ROBERTS: The key in Lochner is that we were talking about regulation of the States, right, and the States are not limited to enumerated powers. The Federal Government is. And it seems to me it's an entirely different question when you ask yourself whether or not there are going to be limits in the Federal power, as opposed to limits on the States, which was the issue in Lochner.
I am not a big fan of the Massachusetts health plan,but it's disingenuous to ignore the key difference between the exercise of state power and federal power.
In the case of Lochner v. New York (1905) (now discredited), referenced above, the Supreme Court overturned a state law limiting the hours bakers could be forced to work. Subsequently, courts have recognized that though the federal government is one of enumerated powers, state legislatures have a more general "police power" -- an ability to legislate for the "general welfare," as it were, that the federal government lacks.
So one can argue the merits and the wisdom of the Massachusetts plan . . . but unlike ObamaCare, which seeks to regulate all Americans, there's no reason to believe it's unconstitutional.
This is, of course, a key distinction for all those who care about the concept of federalism.