Historians have debated the factors that led to Johnson 's surprise decision . Shesol says Johnson wanted out of the White House but also wanted vindication ; when the indicators turned negative he decided to leave . Gould says that Johnson had neglected the party , was hurting it by his Vietnam policies , and underestimated McCarthy 's strength until the very last minute , when it was too late for Johnson to recover . Woods said Johnson realized he needed to leave in order for the nation to heal . Dallek says that Johnson had no further domestic goals , and realized that his personality had eroded his popularity . His health was not good , and he was preoccupied with the Kennedy campaign ; his wife was pressing for his retirement and his base of support continued to shrink . Leaving the race would allow him to pose as a peacemaker . Bennett , however , says Johnson " had been forced out of a reelection race in 1968 by outrage over his policy in Southeast Asia . " After Robert Kennedy 's assassination , Johnson rallied the party bosses and unions to give Humphrey the nomination at the 1968 Democratic National Convention . Personal correspondences between the President and some in the Republican Party suggested Johnson tacitly supported Nelson Rockefeller 's campaign . He reportedly said that if Rockefeller became the Republican nominee , he would not campaign against him ( and would not campaign for Humphrey ) . In what was termed the October surprise , Johnson announced to the nation on October 31 , 1968 , that he had ordered a complete cessation of " all air , naval and artillery bombardment of North Vietnam " , effective November 1 , should the Hanoi Government be willing to negotiate and citing progress with the Paris peace talks . In the end , Democrats did not fully unite behind Humphrey , enabling Republican candidate Richard Nixon to win the election
1968 Democratic National Convention
1968 Democratic National Convention
Lyndon B. Johnson