Gary Hart?God, I hated that guy.
I think it was Senator Paul Simon - I think he was the one - who actually said that he was running for President despite having virtually no disagreements on issues with Hart because "we need someone reliable." And I think it was the Dukakis campaign's polling that said, "I never polled where a front-runner had that many negatives."
The same pollster btw (Tubby Harrison) was the ONE DEMOCRATIC POLLSTER who was warning the Hillary campaign (and the Bernie camp) in 2016, "Trump CAN win this, and there IS a 'silent Trump' vote, so you'd better add 3-4 points to what your polls are showing he has."