The two great revolutions of the eighteenth century—the American and the French had each in turn and in its own way a profound influence not only on the history of the United States and of France, but directly or indirectly on the history of the whole world.
These two powerful currents had a common source in the French ideological movement before the Revolution. The development of American revolutionary thought was of course more closely linked to the English ideology, but there was much contact and cross influence between the English and the French philosophers. Further, the French political and philosophical literature was directly accessible to Americans without intermediary English works. We have only to mention Montesquieu and his principle of the separation of powers which serves as the basis of the Constitution of the United States. Also, the American Revolution influenced in turn political developments in France. One finds the roots of the Declaration of the Rights of Man and of the Citizen not only in France but in America as well.