The chapters of this book were written as papers to be discussed at the Center for the Study of Democratic Institutions. This was a continuing project and was contributed to not only by the Senior Fellows of the Center but by many Visiting Fellows during several years. After discussion the papers were revised and gradually assumed their present form.— The papers were the background for a succession of constitutional models. These served to focus and to make more precise the constitutional changes believed to be necessary after nearly two hundred years. There were frequent modifications of the model, and the number of revisions grew to forty. Still more are in prospect to meet the criteria of the papers.