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Since the mile of the nineteenth century European community had understood that nation could develop only under the ideas of nationalism, liberties and independence within the state, where people live, and where their interests and aspirations are reflected in current legislature. At the same time, nationalism in different European states gained radical features, such as expansion, superiority over other nations and struggle for new territories, markets and zones of economical and political interest. From one side these were colonial interests of European superpowers, with liberal governments as France and Great Britain, who were entering the new age in their development called imperialism and from the other side there were "old-fashioned" monarchies who saw the only way to prosperity in conquest and colonialism. The first case that brought these contradictions to surface was a Crimean War, when Russian and declining Ottoman Empire with allies in the face of Britain and France fought for domination in Black sea, then it was Berlin congress, which finished Russo-Turkish war of 1876-1878.
But by the means of repartitioning Europe, changing maps and establishing new states, imperial interests of major European superpowers could not be solved, as they dream about the whole repartition of colonial world. But they met the counter force in the face of nationalism of oppressed nations, who as well wanted to fight for independence and were not satisfied by territorial ambitions of European major powers.
All these contradictions (imperial and nationalistic) brought Europe and global community to WW1, which had to solve burning problems of European geopolitics by means of blood, cruelty and gunpowder. In order to see the most objective solution to of the problem it's important to refer to Woodrow Wilson's "14 points," who being an independent observe proposed the most reasonable solution to further conflicts at least on the territory of Europe: "to refuse from any colonial claims on European continent and to give the right to self-determination and establishing governments to every nation."