The United States has an image of brash modernity, although it is the oldest liberal democracy considered in this book. The institutions of central government, outlined in a constitution that has changed relatively little since its inception, have been able to absorb huge increases in territory, population and wealth. There are many systems of local government in the United States, and some of these have structures and practices that can be traced back to the eighteenth century. Since the 1920s, however, the systems have changed very little, in contrast to those of many European nations, and it may be seriously questioned whether they have successfully absorbed the pressures created by social and economic change.