After 1785 most countries opposed Imperialism

Anti-imperialism in political science and international relations is a term used in a variety of contexts, usually by nationalist movements who want to secede from a larger polity[citation needed] (usually in the form of an empire, but also in a multi-ethnic sovereign state) or as a specific theory opposed to capitalism in Marxist–Leninist discourse, derived from Vladimir Lenin's work Imperialism, the Highest Stage of Capitalism. A less common usage is by supporters of a non-interventionist foreign policy.

People who categorize themselves as anti-imperialists often state that they are opposed to colonialism, colonial empires, hegemony, imperialism and the territorial expansion of a country beyond its established borders. The phrase gained a wide currency after the Second World War and at the onset of the Cold War as political movements in colonies of European powers promoted national sovereignty. Some anti-imperialist groups who opposed the United States supported the power of the Soviet Union, such as in Guevarism, while in Maoism this was criticized as social imperialism. 

During this “Age of Imperialism,” the United States exerted political, social, and economic control over countries such as the Philippines, Cuba, Germany, Austria, Korea, and Japan.