In "The White Man's Burden," written in the aftermath of the Spanish-American War and the American annexation of the Philippines, Kipling frames imperialism as a sacrifice the white race makes for a "sullen" and "thankless" people. These people are depicted as childlike and in need of the adult guidance of a superior race.
Imperialism occurs when one more dominant nation takes over and runs another nation or people for its own benefit. Kipling's argument in his poem that this conquest is actually a favor to the occupied nation is an example of a false ideology (set of ideas) that whites devised to justify their exploitation of native peoples.
Kipling's poem crystallizes that false ideology. In urging America to become an imperial power over the Philippines, he depicts the white Americans as bringing the benefits of their civilization and adult maturity, along with other virtues, to people not really capable of appreciating them. The Americans, according to Kipling, have taken on a "burden" because of their nobleness and superiority. They are the ones to be pitied, not the oppressed natives. As Kipling puts it:
Take up the White Man’s burden—
Send forth the best ye breed—
Go send your sons to exile
To serve your captives' need
To wait in heavy harness
On fluttered folk and wild—
Your new-caught, sullen peoples,
Half devil and half child.
In reality, the Americans came to the Philippines for their own benefit, not to "serve" their "captives' need."