Imperialism involves one state exerting political control and economic exploitation over weaker states. Colonialism is when a state politically controls another, while annexation incorporates a state into another state's territory. Social Darwinism was used to justify imperialism, arguing stronger societies had a right to rule weaker ones. The "White Man's Burden" asserted white men had a duty to civilize primitive countries. Racism and paternalism characterized the missionary impulse to convert indigenous peoples. The Scramble for Africa in the 1800s saw European powers invade and occupy the continent, except for Liberia and Ethiopia. Nationalism promoted pride in one's country through military and economic strength. Colonized peoples often rebelled against foreign domination.