On April 4, 1968, a shot rang through a throng of striking garbage workers in Memphis, Tennessee. Who fired the gun is still being debated, but the result is not: Martin Luther King, Jr., was killed at the young age of 39 on the balcony of the Lorraine Motel.

It was actually King's second attempt to stand with the Memphis workers, part of his broader effort to fuse the black freedom movement with the labor movement for a national "Poor People's Campaign" that could tackle what King increasingly saw as the real problem facing the country: economic injustice. As historian Michael Honey relates:

When [King] attempted to lead a mass march on 28 March, it turned into window breaking by black youths and a murderous riot by the police. This forced King to return again, vowing to lead another march, in defiance of a court injunction. On the night of 3 April, again at Mason Temple, he reviewed the history of the freedom movement, and called for a renewed solidarity between all peoples, reminding his audience that "either we go up together or we go down together."

King was killed the next day, and along with it went many of the hopes of a broad and successful inter-racial movement for economic justice. King's turn in the late 1960s to promote a broader agenda against war and greed, usually overlooked by the mainstream media when the MLK Holiday rolls around, was a critical moment that could have sent the country in a radically different direction.

My favorite King piece is "Letter from a Birmingham Jail," his 1963 missive against "liberal" Alabama clergy who scolded him for, among other things, being too radical, too impatient, and being an "outside agitator." It's a good read, has many of his best quotes, and still resonates today -- it's the first thing I hand to those who, in the face of some glaring injustice, call for "going slow" or otherwise vascillating when conditions call for action. As King tried to show, we have more power than we know, and history is made when we stand together and use it.