The ordinary meaning of security is physical protection. This the state provides. It offers protection both from other individuals and from other states. In addition to law, it provides national defense. In the twentieth century the state has assumed responsibility for something else: the economic well-being of its citizens. Governments have undertaken to provide not only for the common safety but also, in some manner, for the general welfare.

This more recent responsibility is a legacy of the industrial revolution. New techniques of production have made wealth available on a scale previously unimagined. The belief has spread that governments can encourage, foster, and even supervise these techniques. This belief is most firmly a part of the socialist tradition. In Communist countries, whose governments are offshoots of that tradition, the state has full control of virtually all legal economic activity. In the non-Communist world, management, although not ownership or complete control, of the national economy is generally taken to be one of the duties of the state.

The new responsibility for securing the national well-being is a legacy, as well, of the French Revolution and the political developments that it set in motion. Once it became an article of public faith that the state had the capacity to encourage the creation and take a hand in the distribution of wealth, the conviction took root that it had the obligation to do so.