“King voted Republican in 1956, and his father had endorsed Nixon in 1960.” — Michael O’Brien, “John F. Kennedy: A Biography,” p. 485.
MLK Sr. endorsed JFK at the last minute, after Kennedy called Coretta Scott King.
Yes, that's what I said. But the claim of Jr. having been a Republican, registered or otherwise, is what is in dispute. Ostensibly Jr. would've been eligible to vote with the 1950 mid-term elections. But I have yet to unearth what his voting record was during that period, if he even did vote (given the obstacles most Southern Blacks had). Many of the more leftist Blacks in the South in the '50s that were activists were already aligned with the national Democrats.
But the basic point of this was would MLK, Jr. been a Republican or Conservative by today's standards, and the answer to that is a firm "no." He was a fairly committed Socialist and moving further leftward throughout the 1960s. I've puzzled over why this obsession with a man actively seeking martyrdom AFTER he had accomplished his goal with the CRAs, he inflicted more harm on his children than anything else, and they needed their father above all, not a symbol. Had he not been the victim of assassination, he'd have continued his pursuit of trendy, far-left causes well into the '70s and '80s and doubtless would've been about as well regarded as Je$$e Jack$on or Al Sharpton.