Congress has crossed a fundamental constitutional line. Neither the fact that every individual has some discernible impact on the economy, nor that virtually everyone will at some point in time use health-care services, is a sufficient basis for federal regulation. Both of these arguments, advanced by ObamaCare’s defenders, are flawed because they admit no judicially enforceable limiting principle marking the outer bounds of federal authority.

On the left and right, legal thinkers too often forget that Congress has no constitutional power simply to regulate the economy. Rather, that power comes from a series of discrete authorities—to regulate interstate and foreign commerce, to tax, spend and borrow, to coin money and fix its value and so forth—that together allow it broad control over the nation’s economic affairs. As a result, congressional efforts to address national problems may well be less economically efficient than would a more straightforward exercise of police power. The Constitution subordinates efficiency to guarantee liberty.

The Constitution divides governmental power between federal and state governments so that one may check the other. This requires that the electorate be able to tell, especially on Election Day, which government is responsible for which policies and regulations with which we live.