Different time for sure, but in 1968, the most disgusting man ever to hold the presidency, LBJ, announced he wasn't running for reelection at the end of March with the infamous '68 convention in Chicago still months away at the end of August.
The LBJ 1968 situation was radically different—lets look at the primary season prior to his withdrawal:
New Hampshire March 12: LBJ (write in) 50% McCarthy 42%
March 16: RFK announces he will challenge LBJ
March 31: LBJ withdraws after polls in Wisconsin showed him at 12%
https://en.wikipedia.org/wiki/1968_Democratic_Party_presidential_primaries
Flash forward to today—there are no serious challengers to Biden on the Democratic side:
Let us look at the polls—nationally Biden has 70% support of Democrats and the trend has been stable for months:
https://projects.fivethirtyeight.com/polls/president-primary-d/2024/national/
Biden won New Hampshire easily with write ins.
Next up—South Carolina—polls show Biden at 69%.
Conclusion: The numbers say that Biden will be the Democratic nominee.
Anyone claiming otherwise needs to produce strong evidence for their claims. Imho they have failed to do so to date.
I dunno about that.....there's some neck and neck aholes....out there.