You mean like Kennedy and Johnson?
I was too young at the time to really understand what policies Kennedy and Johnson supported. By the time Johnson was elected, I had formed an opinion of him that he was a rattlesnake. I based that on his escalation of the Vietnam War and his Great Society programs, not to mention his likely involvement in JFK’s death.
JFK was a mess in his personal life, but did not seem as far to the left on Vietnam. Bobby was better than either of them in a lot of ways.
I think Reagan and Bush agreed on the bigger issues, as did Carter and Mondale before them. I also think Obama and Biden are simpatico.