The letter responded to several criticisms made by the "A Call for Unity" clergymen, who agreed that social injustices existed but argued that the battle against racial segregation should be fought solely in the courts, not the streets. As a minister, King responded to these criticisms on religious grounds. As an activist challenging an entrenched social system, he argued on legal, political, and historical grounds. As an African American, he spoke of the country’s oppression of black people, including himself. As an orator, he used many persuasive techniques to reach the hearts and minds of his audience. Altogether, King’s letter was a powerful defense of the motivations, tactics, and goals of the Birmingham Campaign and the Civil Rights movement more generally.