In the preparation of a book intended to give to students an intelligent conception of the Constitutional Law of the United States, both state and federal, it is essential that the historical development of those institutions and ideas of government which have become characteristic features of our system be noticed, that the practical organization of the government as provided for be explained, and that the interpretation which has been put upon the provisions of constitutional instruments in the solution of difficult and important questions which have arisen shall be stated; and it is especially important that the proper relationship between these various divisions of the subject shall be maintained.

I have endeavored, therefore, to make such references to English institutions and the institutions prevailing in the Colonies prior to independence, and to call attention to such of the important reforms in government, for which the English people and the Colonists had struggled, as may be necessary to explain the nature of the state and federal governments provided for in our written constitutions; for it ought to be borne in mind that constitutional law with us involves the correct interpretation of formal instruments of government, framed to meet supposed difficulties and to avert dangers suggested by experience. The language and purport of these instruments are never to be lost sight of in attempting either to rightly comprehend the system of government provided for or to determine what is within the scope of constitutional law, and therefore fundamental, as distinguished from that which is the result of mere practice or statutory provision, and in its nature transitory and mutable. It is true that constitutions may be amended, and yet, whether we look at the constitution of any particular state or at that of the federal government, we discover that thus far in our national history there has been little tendency toward any radical change in the form of government first established. Our constitutional system may therefore be regarded as substantially permanent, the result of national development before it was molded into final form, and of constitutional interpretation after such final form was given to it by the adoption of the constitutions of the thirteen original states and the federal constitution.

This book is not, on the one hand, a theoretical exposition of the general principles of government, nor, on the other, a mere description of the workings of the state and federal governments and their various departments. But, as its title imports, so far as the accomplishment corresponds to the purpose, it is an exposition of the principles of an established system; and it is intended to afford to the reader an explanation of the important events of the history of our government, and the means of intelligently comprehending the problems constantly arising, the solution of which will make our constitutional history of the future. In short, if the book serves its purpose, it will enable the person who intelligently uses it to reach a rational and correct conception of the nature and meaning of the constitutions of the United States and of his state, and to understand the essential features of the governments provided for by such constitutions.

In attempting to depict accurately our entire constitutional system in due proportions it has been necessary to give a larger share of attention than is usually given in works on constitutional law to the nature and functions of the state governments, and to the division of powers between them and the federal government. The state governments are still the repositories of broad and very important powers, and notwithstanding the increased exercise of power by the federal government, there is manifested in our recent constitutional history a persistent attachment to the theory of local self-government which must not be lost sight of in estimating the present trend in the development of our institutions.

I have taken advantage of the opportunity afforded by a new edition to make some changes in the text that may perhaps render it clearer and more accurate and to make additions on points suggested by recent decisions of the Supreme Court of the United States.

Emlin McClain.

Iowa City, June, 1910.