Simple POD, What If LBJ Doesn't make his now infamous speech that night on March 31st, 1968? What If he decides to continue his candidacy? How might this effect the Primary season with LBJ going head to head with RFK and McCarthy? Does he recieve the nomination? IS there any possible way thay he may win the general against Nixon? If he does what might an Second term of LBJ look like?Does he even complete his term with his heart complications? What are some possible long term effects?
I'm going to assume that somehow this butterflies away RFK's death in Los Angeles on the basis that this non-declaration means the primaries bear little resemblence to those in OTL. My sense in those, by the way, is that while LBJ doesn't win many outside the south/southwest, he wins just enough or runs second just well enough to stay in the mix throughout.
In the Chicago convention, you have a sitting president facing strong challenges from one outspoken anti-war candidate in McCarthy and a strong charismatic challenger in Kennedy. I think that would lead to an all-out floor fight with the possibility of the first multiple-ballot convention in decades. I believe that at the time, a two-thirds majority was needed in the Democrats' convention to win a nomination; my guess is that a Kennedy-McCarthy coalition wouldn't have two-thirds of the votes to put a compromise candidate over the top, and that Johnson by himself wouldn't be able to do so either.
Compromise is almost out of the question, since the convention is a microcosmic referendum on Johnson's policies. About the best one could hope for in terms of preserving unity is that there would be sufficient defections from Johnson to allow a Kennedy-McCarthy coalition to put a compromise candidate over the top in repudiation of Johnson. But that would be a pyrrhic victory at best: that kind of internal dissent among the Democrats would make Nixon's election virtually a lock. Indeed, said compromise candidate would probably run third in the deep south behind Wallace and Nixon.
Nixon might not have a de facto majority in either house of Congress, but the wounds from the convention would linger, splitting the Democrats, with many lining up with the Republicans on various issues. In fact, the lingering split might delay selection of a speaker of the house or indeed the election of a coalition speaker (coalition, that is, of conservative Democrats and most Republicans). The shift of the south to the GOP would probably be hastened a few years when all is said and done.