From his book "Where Do We Go From Here", which was written after the Civil Rights Act and National Voting Act, MLK suggests quite radical reforms to United States economic policy. Not only did he advocate for a full employment economy, he also thought all americans should make a government sponsored guaranteed income to eliminate poverty. Had he not been assassinated, he may have been labeled as too radical/communist, and thus, his persona would not be as mythologized.

While arguing civil rights with a friend, I was told that near the end of his life, he started believing that non-violent protests were not effective enough, and started considering slightly more violent or aggressive options. Is there any truth to this?

King's views on militarism and economic justice shifted leftward as he grew disillusioned with persistent black poverty and the Vietnam War. He grew more hostile towards northern allies after he faced even more vicious resistance to his nonviolent tactics. See the 1966 Chicago campaign.