During the generations of general peace between 18l5 and 1898, American idealism and realism remained compartmentalized, the former residing in the realm of opinion, ideas, and moral posturing, the latter existing in the realm of policy and action. On occasion, the levers of policy were put at the disposal of moral purposes, but not in a manner that would deflect the basic guidelines of American external policy. But in 1898 the compartments began to break down; the surge of popular passion on behalf of other peoples, against which realists such as Hamilton had warned, erupted on behalf of moral crusades in defense of Cuba, the Philippines, and China.
Following the outbreak of the Cuban revolt in February 1895, the Cuban junta, with headquarters in New York, supported by the Cuban League, its American counterpart with branches in all large cities, launched a campaign to involve the United States in this renewal of the Cuban struggle for independence. Cuban rebels understood the peculiar appeal of humanitarian causes to nineteenth-century Americans. The Spanish government, by employing measures of extreme repression, played into their hands. The Madrid government damaged its image almost beyond recall when, in 1896, it dispatched General Valeriano Weyler to Cuba, where he proceeded to herd civilians suspected of rebel leanings into concentration camps. President Grover Cleveland resented the Cuban assault on American emotions and held to a policy of neutrality against the rising tide of pro-Cuban sentiment. The Spanish government offered Cuba autonomy, but President William McKinley's decision of 1897 to oppose any arrangement unacceptable to the revolutionaries, whose minimum goal was indepen-dence, eliminated every possibility of a peaceful Cuban settlement. Washington gave Spain the choice of capitulation or war. The sinking of the battleship Maine on 15 February 1898, along with other unfortunate incidents, aroused a congressional demand for war, a responsibility that McKinley accepted to protect the principle of executive leadership in external affairs. On 21 April the United States broke diplomatic relations with Spain and embarked on a war for Cuban independence.
Few Americans attempted to justify the war except in humanitarian terms. Such motives were not strange to American liberal thought, but before 1898 they had never governed action. Whether it was a people's war, forced on a reluctant administration, or one reflecting a slow, steady evolution of presidential policy, it did not result from any deliberate weighing of interests and responsibilities. The president asked for war in the name of humanity and civilization as well as endangered American interests. "Our own direct interests [in Cuba] were great," observed Theodore Roosevelt in his An Autobiography (1913), "but even greater were our interests from the standpoint of humanity. Cuba was at our very doors. It was dreadful things for us to sit supinely and watch her death agony." Similarly, Senator George F. Hoar acknowledged that the American people could not "look idly on while hundreds of thousands of innocent human beings, women and children and old men, die of hunger close to our doors." Had Cuba not lain off the coast of the United States, there would have been no war of liberation in 1898. Previous generations of Americans had sought new deals for Greeks and Hungarians in vain. In 1898 sentiment mattered because it was directed at oppression by a weak power in an adjacent region where the United States held the clear strategic advantage.
Commodore George Dewey's destruction of the Spanish fleet in Manila harbor on 1 May did not presage an annexationist movement in the Pacific. But almost immediately a number of expansionists, both inside and outside the administration, clamored for the occupation and annexation of the Philippines—islands in the western Pacific where other nations possessed greater naval power than did the United States. Succumbing to expansionist pressure, the administration, in its instructions to the peace commission dated 16 September, announced its intention to acquire the Philippines. McKinley rationalized the decision by citing the country's obligation to humanity. This theme dominated his speeches during his midwestern tour in October 1898. Always he dwelt on the accidental nature of the country's de facto possession of the Philippines and its special responsibility to the Filipinos that, he insisted, flowed from that possession. He declared at Cedar Rapids, Iowa, that "we accepted war for humanity. We can accept no terms of peace which shall not be in the interests of humanity." He repeated that appeal in Omaha: "The war was no more invited by us than were the questions which are laid at our door by its results. Now as then we will do our duty." Later, in Boston, he declared that "our concern was not for territory or trade or empire, but for the people whose interests and destiny, without our willing, had been put into our hands." Thucydides, the Greek historian, wrote many centuries earlier: "You cannot decline the burdens of empire and still expect to share its honours." McKinley, however, failed to dwell on the burdens of empire at all. It was not strange that the American people, given the simple choice between humanity and irresponsibility, assured him of their overwhelming support.
Realists charged that the acquisition of the Philippines was a serious departure from the country's traditional conservatism in foreign affairs. They noted that the annexation of distant territories would entail financial and military burdens with few rewards. The United States, wrote Andrew Carnegie, lacked not only the naval power to protect the Philippines but also the will to create it. The former U.S. Senator Carl Schurz feared that Philippine annexation would so completely over commit the nation that it would reduce the United States to complete reliance on the British fleet. Such reliance would demand a heavy price. "If we do take the Philippines," he predicted, "and thus entangle ourselves in the rivalries of Asiatic affairs, the future will be…one of wars and rumors of wars, and the time will be forever past when we could look down with condescending pity on the nations of the old world groaning under militarism and is burdens." Senator Augustus O. Bacon of Georgia foresaw "peace at evening, perhaps, with no certainty but that the morrow will find us participants in a world's war." Against such arguments Senate approval of the annexation treaty came hard. The final vote was fifty-seven to twenty-seven, one more than necessary to gain the required two-thirds.