What were Johnson’s numbers when he made the decision not to run in 1968?
Around 40%.
Johnson started out at 75% in the fall of 1963, fell below 50% in spring '66, then below 40% in spring '67.
By the end of his term in 1968, he was back up to 45%.
Interesting to note that Ford, Reagan, and Clinton all fell to 40% but then recovered to over 50%.
But in each case the 40% level happened early in their first terms.