According to the author, why does LBJ originally decline the support of the southern Senators for the presidential nomination as noted in the nonfiction book, Master of the Senate: The Years of Lyndon Johnson?

LBJ originally declines the support of the southern Senators for the presidential nomination because he fears humiliation. This feeling as based on Rayburn's assessment of Stevenson's good chances to win the nomination. LBJ simply informes reporters that he is only the south's favorite son, not the favorite in the election.