How i can find out the ideological concepts of Langston Hughes's words used in his poetry?

He used concepts of American democracy as an emotional tool in his poetry to get people to hold to American principles for black civil rights. In the 40s and 50s, American patriotism was very different than today, so he could use poetry to appeal to people's ethics, like in "Let America Be America Again," and "I, Too, Sing America"