George McGovern selects Tom Eagleton 1

Not a bad choice, but really bad background checking. After the nomination it was revealed that Eagleton had undergone psychiatric treatment, and ultimately withdrew from the ticket, being replaced by Shriver.

A lot of people have had psychiatric treatment, but it does carry a stigma, and Eagleton should have known that and revealed it. Ambushing McGovern with the revelation was irresponsible.

Not that it really mattered. McGovern couldn't have beaten Nixon that year if he'd had Jesus Christ on the ticket.