Perhaps a cliche in alternate history, but we don't really focus on it as much as we should. What if President Nixon avoided his fatal shooting on that Memphis street in 1965?
Well, President Smith's tenure didn't turn out so badly, and Diem remained in power until his death. Civil Rights didn't turn out so well, remember the filibuster on the VRA of 1967? When Donald Nixon was imprisoned during Kennedy's first term after the Hughes loan was revealed, it cast a pall on Nixon's reputation. That was before President RFK had to do damage control after the revelations of Jack's affair with Judy Exner. I still remember that.