Chomsky praises him, saying he was vilified, but he was crucial to making change. Two years ago, the New York Times published an excellent transcript of his final sermon, annotated by Nikita Stewart to clarify the events that provoked some of his words. It's his "I've been to the mountaintop" speech made four years after the Civil Rights Act passed, and one day before his death. Here's an abridged version (or listen to it in full here). The bold is all mine; his words have been repeated by Chomsky and Hedges and Timothy Snyder. Hopefully we'll listen one day.
It is no longer a choice between violence and nonviolence in this world; it’s nonviolence or nonexistence. That is where we are today. And also in the human rights revolution, if something isn’t done, and done in a hurry, to bring the colored peoples of the world out of their long years of poverty, their long years of hurt and neglect, the whole world is doomed. . . .