In general, American political theory has been struck off in connection with controversies over specific subjects. The rights of man, the consent of the governed, the right of revolution, were discussed in relation to the Revolution of 1776. The causes of this scarcity of political theory are various. It may be urged that the lack of theory is due to the tendency of the American or the Englishman toward action rather than reflection - to be practical rather than philosophical. Of French thinkers by far the strongest influence exerted on American theory was that of Montesquieu, through the famous doctrine of the tripartite division of governmental powers. In recent years the influence of the German political scientists has been most pronounced. This influence began with the work of Francis Lieber as an instructor in American schools and an investigator in the field of political science.