By the time of the Civil War the first American expansive drive was over. The most obvious objectives of manifest destiny had been achieved, and the frontiers of the United States were logically satisfying. The country stretched from sea to sea. To the north lay Canada, a region which, it could be argued, must some day inevitably fall to the United States, but whose accession it was neither necessary nor desirable to hasten. To the south lay Mexico, arid and uninviting, and peopled by men whose stock, language, religion and traditions were suspect to most Americans.

Within the United States itself there was ample land to occupy the energies of a vigorous people. Even before the Civil War manifest destiny and the lure of the West had not been the only impulse to expansion. Competition between North and South for the control of the West, as a source of both economic and political strength, had been as important in determining the urgency of the rush to the Pacific. The genuine expansionists had hoped to divert Americans from their sectional quarrel by invoking the imperial dream; but their failure to do so did not slow an advance which the quarrel itself turned into a race. When the Civil War was won and lost, the most obvious goal of expansion had been achieved and the most impelling motive of expansion removed.