Governmental relations with European states were disturbed at times by crises of greater or less importance. The proximity of the United States to and interest in Cuba compelled the Government to recognize the political existence of Spain; a French army was ordered out of Mexico when it was felt to be a menace; the presence of immigrant Irish in large numbers always gave a note of uncertainty to the national attitude towards Great Britain. The export of cotton from the Southern States created industrial relations of such importance with Great Britain that, during the Civil War, after the establishment of the blockade on the Confederate coast, wisdom and forbearance were needed on both sides to prevent the breaking out of armed conflict. But during the last third of the century, which was marked in this country by an extraordinary industrial evolution and an increased interest in domestic administrative issues, the attitude of the United States towards Europe, except during the brief Venezuelan crisis and the war with Spain, was generally characterized by the indifference which is the natural outcome of geographical separation. In diplomatic language American foreign policy, so far as Europe was concerned, was based upon the principle of "non-intervention." The right to manage their affairs in their own way without interference was conceded to European Governments and a reciprocal attitude was expected of them. The American Government followed strictly the purpose of not participating in any political arrangements made between European states regarding European issues. Early in the life of the nation Jefferson had correlated the double aspect of this policy: "Our first and fundamental maxim," he said, "should be never to entangle ourselves in the broils of Europe; our second, never to suffer Europe to intermeddle with cis-Atlantic affairs." The influence of John Quincy Adams crystallized this double policy in the Monroe Doctrine, which, as compensation for denying to European states the right to intervene in American politics, sacrificed the generous sympathies of many Americans, among them President Monroe himself, with the republican movements across the Atlantic. With the continued and increasing importance of the Monroe Doctrine as a principle of national policy, the natural and reciprocal aspect of that doctrine, implying political isolation from Europe, became more deeply imbedded in the national consciousness.