"Was Random House aware that [Joe McGinniss] was making a desperate overtime bid to save face?"

"And if so, why did it allow him to come forth with most of those tawdry accusations without proof or proper sourcing?"

McGinniss's sleaziness has been well understood. Let's focus on Random House, the venerable publishing house.

In the email [at the link], McGinniss reveals that his manuscript, then under legal review at Crown/Random House, could not prove its most headline-grabbing allegations. And yet, many of these “salacious stories” that lacked “proof” (in McGinniss’s own words) ended up in the book, and on televisions everywhere during the author’s current media tour … without proper sourcing, and without any apparent new evidence to support them.

It's hard for a public figure to sue for defamation in the United States, but this email may be the proof of reckless disregard for the truth that Sarah/Todd/Bristol Palin would need.

That doesn't mean they should sue. It would boost the profile of McGinniss and his book and shine a spotlight on his various allegations.