Romney came in and cleaned up a corrupt organization; there's no way they can credibly pin that corruption on him. There's a difference between stretching the truth (such as in the Foley incident), something the media can do very well, and turning it around completely, something that usually discredits the accusing party.
It doesn't work that way, kid. It's just baggage and mud.
Pick someone who has neither. That's how Abraham Lincoln won. That's how President Bush won (and the baggage/mud that turned up in the final week of his 2000 campaign almost sunk him).
And that also helped President Reagan win.
You don't want Watergate baggage. Why spend hours explaining to people that Nixon had no motive for bugging Democrats in the Watergate hotel 3 months before his election landslide (when he was already at the top of the polls)?!
That sort of thing gets in the way of your message and puts you on the defensive from Moment One.
Bad strategy.