According to federal Judge Gladys Kessler of the DC US District Court,  the powers granted to the federal government on the Commerce Clause extend to regulating "mental activity."  Ruling on an ObamaCare challenge brought by 2 individuals, the good Judge made the leap from "physical activity" to "mental activity" in extending the reach of the federal government.  This is not a joke.  Read the 64 page decision here.  According to Judge Kessler:

As previous Commerce Clause cases have all involved physical activity, as opposed to mental activity, i.e. decision-making, there is little judicial guidance on whether the latter falls within Congress's power...However, this Court finds the distinction, which Plaintiffs rely on heavily, to be of little significance. It is pure semantics to argue that an individual who makes a choice to forgo health insurance is not "acting," especially given the serious economic and health-related consequences to every individual of that choice. Making a choice is an affirmative action, whether one decides to do something or not do something. They are two sides of the same coin. To pretend otherwise is to ignore reality.

The  ruling by the Clinton appointee, U.S. District Court Judge Gladys Kessler of the District of Columbia continues the pattern of Democratic-appointed judges siding with the Obama administration and Republican judges siding with the plaintiffs in ruling the mandate unconstitutional. Kessler's ruling comes in a case brought by individual plaintiffs, where as the two decisions striking down the mandate have come in cases brought by 27 states, based in Virginia and Florida.