It accomplishes its purposes not through legal supremacy but through institutional cooperation with the states. The states' role lies not in governing a separate sphere of authority but in their independent authority to administer federal schemes. Such a federalism is not intrinsically incoherent. It is the federalism of Germany, Switzerland, and Europe, as Justice Breyer observed in his Printz dissent. Under this view, there is nothing objectionable in the federal commandeering of state officers.
Cooperative federalism does, however, have a political and judicial tradition in America.
Politically, cooperative federalism can be traced to the Progressives, who hoped to harmonize national aspirations with the virtues of localism. Cooperative federalism became dominant, both as a matter of political practice and judicial doctrine, under the New Deal. As the political pedigree suggests, the shift from constitutional to cooperative federalism is tied to the growth of government. Constitutional federalism constrains government. The real, much deeper divide runs between constitutional constraint and democratic aspirations, a divide that ran through the Bush v. Gore opinions.