The conservative co-opting of MLK has occurred for the past two decades. I had thought this was obvious by now to everyone, even though 30 years they would not have done so. Paul Gottfried recent book Conservatism in America (2007) goes into the whos and whys (IIRC). National Review used to condemn MLK’s radicalism back in the ’60s, but now just the opposite.
I do recommend it, as I recommend Gottfried’s other books on the managerial state in Europe and America. Having read a few of your comments, please know that Gottfried does challenge Russell Kirk’s welding of “transcendent values” with American conservatism, pointing out the problematic results of that (especially in its reappropriation in neoconservative rhetoric).