"letter from a birmingham jail," penned by martin luther king, jr., in 1963, is a classic defense of which form of political protest?

It is a defense of the form of peaceful protest which he had been so fond of in his time, and with which he achieved so much. In this letter he defends his political protesting by outlining the four steps which need to be followed in any event of a campaign of peaceful protest, "In any nonviolent campaign there are four basic steps: 1) collection of the facts to determine whether injustices are alive; 2) negotiation; 3) self-purification; and 4) direct action." He defends his position by saying he has gone through the motions, sat through the formalities with government officials, none of which has been fruitful in helping the which is civil rights, so now it is time for direct, nonviolent action.