Here's Robert Caro on LBJ/JFK and the civil rights bill.
"At the time President Kennedy is killed, that Civil Rights Bill is going nowhere. The Senate was always the great barrier to civil rights with its use of the filibuster. But the bill’s not even in the Senate. It’s not even on the House floor. The House Judiciary Committee has passed it, but they sent it to the Rules Committee, which is presided over by Judge Howard W. Smith of Virginia, the archest of segregationists. He won’t even tell anybody when he will start a hearing. At approximately the same time as the Kennedy motorcade is going through Dallas, John McCormick, the Speaker of the House, is asking Judge Smith, “What’s the schedule? When are you going to start hearings?” Smith is saying, “I don’t know.”
The Washington Post interviews Smith and asks, “What are your plans for the Civil Rights Bill?” He says, “No plans.” That bill is not getting out of the Rules Committee; it’s completely stuck."
Then this: "Three nights after Kennedy’s assassination, Johnson’s going to give his first speech to the joint houses of Congress. Johnson’s not even in the Oval Office yet; he’s still living at home. In the dining room, around his kitchen table, his advisors are drafting the speech. Johnson comes in, and they tell him, “Don’t emphasize civil rights. Don’t make that a priority. You’re going to alienate the Southern Democrats. It’s a lost cause, anyway. It’s a noble cause, but it’s a lost cause. Don’t waste your prestige immediately on it.” And Johnson says, “What the hell’s the presidency for, then?” He makes civil rights a centerpiece of his speech. He puts it in the context of Kennedy’s memory. “This is what he fought for. This is what he wanted.” Sympathy for Kennedy is not the whole story, but it’s a big part of the story of why that Civil Rights Bill gets passed."
So, the claim that LBJ was behind the assassination is made even more illogical by this act by LBJ, by this address to the nation. He is risking, seriously risking, his presidency and any chance of election with this speech and its call for passage of the civil rights bill. It risks alienating the South, a key Democrat voting block, and the chances of election (the Republican nominee was still to be determined). It makes no sense on any level that he would be the mover behind the assassination in order to attain the presidency AND then risk all of that with these actions shortly afterwards.
Finally, here is Caro on JFK: "In those respects [the missile crisis, foreign affairs], Kennedy was among our greatest presidents. You also have to say that in domestic affairs, Kennedy was not effective. His legislative program and the ideals he articulated for Medicare, for tax reform, for civil rights weren’t going anywhere. Would they ever have gone anywhere? If he had a second term, would they have gotten passed? Perhaps, but there’s no sign of that. Both of his two big bills, the tax cut bill and the Civil Rights Bill, were absolutely stalled in Congress."
Full piece here:
https://newrepublic.com/article/115477/robert-caro-lbj-jfk-assasination-and-me