Of all the functions of government, or the State, national defense is generally considered to be the most essential. Ideally, national defense should be a service provided by government to the people. The service entails protection from aggressors outside the State’s jurisdiction, usually foreign States although sometimes foreign terrorists. Yet a government’s ability to provide such protection ultimately rests on its power to wage war. Governments therefore have tended to devote more resources to war than to anything else. Indeed, prior to the advent of the modern welfare State, they usually spent more on war than on all other things combined. Governments were essentially war making institutions that did a few other things on the side. As a result, the history of nearly all governments is dominated by the conduct of wars, the preparation for wars, and the consequences of wars; and this is no less true for the United States government than for any other.

This manuscript therefore surveys the domestic repercussions of past U.S. wars, from the American Revolution through World War II. Not only did the State swell in authority, reach, and intrusiveness while waging war, but also a postwar ratchet effect almost always left government in America more powerful after the fighting was over. Post-war retrenchment was rarely sufficient to bring government back to its prewar levels. The State had assumed new functions, taken on new responsibilities, and exercised new prerogatives. The impacts of modernization, urbanization, economics, demography, complexity, or other domestic developments pale in comparison. Of all the myriad factors that historians have studied and identified as contributing to the evolution, contours, and scope of government at all levels within this country, none is more crucial, pervasive, and ubiquitous than warfare.