<P> Hugo planted a tree in the grounds of his residence on the Island of Guernsey . He was noted in saying that when this tree matured the United States of Europe would have come into being . This tree to this day is still growing in the gardens of Maison de Hauteville, St. Peter Port, Guernsey, Victor Hugo's residence during his exile from France . </P> <P> The Italian philosopher Carlo Cattaneo wrote, "The ocean is rough and whirling, and the currents go to two possible endings: the autocrat, or the United States of Europe". In 1867 Giuseppe Garibaldi and John Stuart Mill joined Victor Hugo at a congress of the League for Peace and Freedom in Geneva . Here the anarchist Mikhail Bakunin stated "That in order to achieve the triumph of liberty, justice and peace in the international relations of Europe, and to render civil war impossible among the various peoples which make up the European family, only a single course lies open: to constitute the United States of Europe". The French National Assembly also called for a United States of Europe on 1 March 1871 . </P> <P> Following the catastrophe of the First World War, some thinkers and visionaries again began to float the idea of a politically unified Europe . In 1923, the Austrian Count Richard von Coudenhove - Kalergi founded the Pan-Europa Movement and hosted the First Paneuropean Congress, held in Vienna in 1926 . The aim was for a Europe based on the principles of liberalism, Christianity and social responsibility . Before the Communist revolution in Russia, Trotsky foresaw a "Federated Republic of Europe--the United States of Europe", created by the proletariat . </P> <P> In 1929, Aristide Briand, French Prime Minister, gave a speech before the Assembly of the League of Nations in which he proposed the idea of a federation of European nations based on solidarity and in the pursuit of economic prosperity and political and social co-operation . Many eminent economists, among them John Maynard Keynes, supported this view . At the League's request Briand presented a "Memorandum on the organisation of a system of European Federal Union" in 1930 . In 1931, French politician Édouard Herriot and British civil servant Arthur Salter both penned books titled The United States of Europe . </P>

Why did some countries after world war ii form what would become the european union