Zaid Jilani in The Intercept:
America’s celebrations of Martin Luther King Jr. typically focus on his civil rights activism: the nonviolent actions that led to the Civil Rights Act of 1964 and the Voting Rights Act of 1965.
The last few years of King’s life, by contrast, are generally overlooked. When he was assassinated in 1968, King was in the midst of waging a radical campaign against economic inequality and poverty, while protesting vigorously against the Vietnam War.
This was a campaign whose intellectual roots were found in a younger King, who grew uneasy with the excesses of capitalism around him even as he focused on civil rights issues. In the summer of 1952, he wrote a letter detailing these concerns to Coretta Scott, whom he began dating earlier in the spring. In that letter, he concluded that “capitalism has outlived its usefulness”:
I imagine you already know that I am much more socialistic in my economic theory than capitalistic. And yet I am not so opposed to capitalism that I have failed to see its relative merits. It started out with a noble and high motive, viz, to block the trade monopolies of nobles, but like most human systems, it falls victim to the very thing it was revolting against. So today capitalism has outlived its usefulness. It has brought about a system that takes necessities from the masses to give luxuries to the classes.
Government officials tracked his growing radicalism, and feared it.
More here. Also see this shameful and shocking letter the FBI sent to MLK, Jr.