[scrabblehack]

The closest thing to it was Eagleton in 1972...the DNC, not the convention, approves the choice.

[RoosterRedux]

In the case of Eagleton, McGovern selected Shriver after the Eagleton pull-out. The DNC approved, but it wasn't their choice to make.

In the case of a Presidential nominee, I would think the second strongest primary candidate would demand the nomination (particularly when that candidate is Bernie).