Not surprisingly given the American anti-colonial, anti-imperialist tradition, the acquisition of territories and colonies as outlined by the Treaty of Paris caused considerable debate. An organization known as the Anti-Imperialist League arose in the US, standing in opposition to American expansion and imperialism. Some of the nation's most famous people, including the writer Mark Twain and the philosopher William James, were leading figures in the Anti-Imperialist League. This vocal minority had many points that still smack of good reason today. However, in the late 1890s, their view did not win out. Instead, pro-imperialism, backed by an ideology of jingoism, carried the day.
The Treaty of Paris, though signed, still had to be passed by two-thirds of the Senate in 1899. The Democrats had enough votes to block passage of the treaty, and for a while it looked as if Senate deadlock was inevitable. Finally, William Jennings Bryan, a leading Democrat and constant opponent of President McKinley, decided to support the treaty. Convincing several of the Democratic senators to change their mind, Bryan barely got the treaty passed in the Senate on February 6, 1899.
In supporting the Treaty of Paris, Bryan had a trick up his sleeve. He knew that if the treaty passed, the nation would see the Republicans, the majority party at the time, as responsible. In the election of 1900, Bryan hoped to run against McKinley on an anti-Imperialist platform, and by passing the treaty, he hoped to associate the Republicans with Imperialism. Bryan expected imperialism to quickly become unpopular, giving the Democrats an issue to criticize the Republicans over. Unfortunately for Bryan, not enough voters were upset about imperialism by 1900 to aid his cause: he still lost to McKinley. Bryan also appeared to vote as he did for ideological reasons reminiscent of British patriarchal colonialism: he suggested that the sooner the US annexed the Philippines, Guam, and Puerto Rico, the sooner the US could prepare them for independence.
The annexation of the Philippines caused major problems, however. The Filipinos had fought with the Americans against the Spanish, thinking that the Americans were there to liberate the Philippines in the same way they were liberating Cuba. When hoped for freedom failed to materialize and the Americans did not go home, the Filipinos felt betrayed. On Jan 23, 1899, the Filipinos proclaimed an independent republic and elected long-time nationalist Emilio Aguinaldo president. The US sent in reinforcements to put down this "rogue" government. Fighting against the Filipino nationalists they had fought alongside months earlier, the US endured two harsh years of battle. Aguinaldo's guerilla fighters put the US through a much more difficult and bloody conflict than the relatively easy Spanish-American War. Still, the Filipino's never had much chance against the superior force of the Americans. On March 23, 1901, the US finally put down the Filipino revolt by capturing Aguinaldo. After being forced to take an oath of loyalty and receiving a pension from the US government, Aguinaldo retired, and never led further revolutions.
The founders of the United States, who fought a revolution to end its own status as a colony of Britain, probably never expected that a little more than a century later the United States would take colonies of its own. From this perspective, America's imperialism during and after the Spanish-American War is quite a shock, which some have called the "Great Aberration." It is therefore not surprising that a strong resistance movement, the Anti-Imperialists, would rise up. However, from another perspective, American imperialism in 1898 was not a sudden abandonment of anti-colonial tradition, but a was logical extension of commercial expansion, something the US had been doing throughout its history. The claim that the year 1898 was an aberration in American history are undermined by the facts. Today, the biggest colonialist of recent history, Great Britain, has relinquished its last colony, Hong Kong. Meanwhile, America still possesses the protectorates of Guam and Puerto Rico, and still has naval bases in Cuba and the Philippines. In this sense, the imperialist effects of the Spanish-American War remain alive even in the present.
The Anti-Imperialist argument was as follows. Since the Filipinos wanted freedom, annexing their homeland violated the basic American principle that just government derived from the "consent of the governed." Second, and perhaps more practically, the Anti-Imperialists felt that American territory in the Philippines would make it likely that events in Asia would involve the US in more conflicts and more wars.