While commemorating the 40th anniversary of Martin Luther King Jr.'s death today, it's important to remember why King was in Memphis to begin with. Last year, Peter Dreier reminded us of the specifics of that mission. (And it's a mission that that continues today.) It's a complimentary piece to read alongside Kai Wright's powerful essay today on King's forgotten radicalism.

It's important to keep this radicalism in mind if you happen across, say, John McCain bringing his "Service to America" tour to Memphis today. And also important to remember that McCain (and conservatives in general) haven't always had the warm-and-fuzzies for the dream of economic and social justice that King gave his life to help make a reality.