Towards such a possibility the nineteenth century has made three great contributions.  During that century great advances have been made in the settlement of political government upon a basis of nationality.  This process has been accomplished partly by throwing off the dominion of some foreign power, as in the case of Belgium, Greece, Montenegro, Bulgaria, Rumania, and Serbia, and the South American colonies of Spain; partly by the closer federal union of independent states, as in the case of Germany and Switzerland; partly by a blend of the two methods as in the case of Italy; and partly by the peaceful dissolution of an unnatural union, as with Norway and Sweden.  Though much still remains to be done before the identification of statehood with nationality even for Europe is completed, and some backward steps have been taken, the growing acceptance of the conception of nationality as a just and expedient basis of government is a powerful guarantee for the persistence of this joint work of liberation and of union.  If, as the result of the settlement following this war, political readjustments are made which fairly satisfy the remaining aspirations after national autonomy, the more pacific atmosphere will favour all opportunities for co-operation between nations.

The second contribution of the nineteenth century towards political internationalism is of a more positive character.  It consists in a series of inchoate and fragmentary but genuine attempts of the Great Powers to work together upon critical occasions in the interests of ‘justice and order’, as they understood those terms, and to embody in acts or conventions some policy which is the result of their deliberations.  This flickering light, called the Concert of Europe, first kindled at the Congress of Vienna, has reappeared fitfully throughout the century.  The treaties, declarations, and conventions, proceeding from these conferences or congresses of the Powers, have marked important advances, not only in the substance of international law, but in the method of legislation.  For whereas, before the Congress of Vienna, all the treaties between states which helped to form the body of international law were the acts of two or, at the most, a small group of states, since that time law-making treaties of general application and of world-wide importance have come into being.  The most noteworthy examples of these general treaties are the Final Act of the Vienna Congress in 1815, the Declaration of Paris in 1856, the Geneva Convention of 1864, the Treaty of Berlin in 1878, the General Act of the Congo Conference in 1885, and the two Hague Conferences of 1899 and 1907.  Having regard to the general character of many of the rules laid down at these conferences, as, for instance, the abolition of the slave trade, the neutralization of certain lands and waters, and the regulation of the rules of war, it is clear that we have to recognize throughout last century the existence of a rudimentary organ of international legislation, very irregular in its operation, very imperfect in structure and authority, but none the less a genuine experiment in international government.