[Diversity Is Our Weakness]

Unprecedented? Both Truman and Johnson were incumbents who withdrew from the race.

---

But both served more than one four year term. Harry did almost 8.

[Right_Wing_Madman]

But both served more than one four year term.

Johnson was president for five years and only elected once, so he was constitutionally eligible to seek re-election and serve another term (22nd Amendment: 10 years max). Truman was not eligible.