"I would point to the fact that that Dr. King's dream began to be realized when President Johnson passed the Civil Rights Act of 1964, when he was able to get through Congress something that President Kennedy was hopeful to do, the President before had not even tried, but it took a president to get it done. That dream became a reality, the power of that dream became a real in people's lives because we had a president who said we are going to do it, and actually got it accomplished."
My reading of this seems to set LBJ over and above JFK in his ability to "get it done" (and implicitly arguing a "competent" candidate (Hillary/LBJ) was more useful than a "change" candidate (JFK/Obama). LBJ was famous for the "treatment" he could deliver in person and for his ability to work legislation through Congress. Still, though I think a significant part of why LBJ was able to "get it done" was the moral authority of the recently slain JFK and the trauma of a stunned nation. Much like after 9/11, the President was able to run the tables on Congress for a time. I think if it had not been for the progressive rhetoric of immediately sainted JFK and of the soon to fall MLK that it would have been much tougher for Johnson to "get it done".
None of this takes away from the fact that LBJ probably showed more political courage than JFK. Kennedy had not gone to the mat for tough legislation in part because he worried about blowing up the Democratic coalition. Johnson bulled it through and did indeed blow up the coalition (being caught in a losing war didn't help). Other than a self inflicted loss in 76 the Republicans were ascendant for the next quarter century.
What is truly sad is that Republicans in the late 1800s abandoned blacks in the south to the tender mercies of the traitors after having expended so much of the nation's blood and treasure to free them and subdue said traitors. U.S. Grant was the last to try and he was finally forced to give up the fight by a recalcitrant Congress and a pro Klan Supreme Court. The Republicans not only lost black voters, they in many ways lost their identity. The whole Civil Rights controversy that roiled the nation in the 1950s and 1960s should have been in large part settled in the 19th Century.