Rudyard Kipling wrote his poem "The White Man's Burden" in 1899. At this time, the US was at war with the Philippine Islands, which wanted to be independent and not owned and controlled by the US. In Kipling's poem, the speaker suggests that it is the responsibility of all supposedly civilized white people to control the supposedly "uncivilized" brown and Black people in different countries. By extension, he argues, it is the responsibility of the US to win the war and keep possession of the Philippine Islands.
In the opening stanza of the poem Kipling, urges the US to "Send forth the best ye breed," meaning that they should send men to help win the war and keep control of the Philippine Islands. In the opening stanza, Kipling also says that the people of the Philippine Islands are "fluttered folk and wild," the implication being that these "wild" people need to be policed, and civilized.
Throughout the poem, Kipling characterizes the people of the Philippine Islands as ignorant and primitive, and in doing so, he adds weight to the implication that these people need to be civilized. In the third stanza, Kipling calls the people of the Philippine Islands "savage," and in the fourth stanza he calls them "tawdry." In the penultimate stanza of the poem, he calls them "sullen peoples."
At the end of the poem, Kipling says that the US needs to win the war to put an end to "childish days." The implication here is that, left to their own devices, the people of the Philippine Islands would be "childish," meaning uneducated, petulant, and incapable of self-government.
Kipling repeatedly uses pejorative language to describe the people of the Philippine Islands to suggest that it is indeed a responsibility, or "burden," of white people to conquer and control their supposedly less civilized neighbors. This is of course a much more palatable rationale for invading another country than simply admitting that the invasion is motivated by imperialist greed.