Ron Klain was Biden’s former chief of staff, and the president of Case Holdings in September 2012. If you look up Klain’s name in the book “Double Down: Game Change 2012” you see that Klain was also Obama’s “lead debate coach”:

Michael Donilon is the brother of Thomas Donilon, who in addition to being Obama’s national security advisor, was also involved in the 2008 debates:

During the 2008 campaign, Mr. Donilon headed President Obama’s general election debate preparation effort.

Thomas Donilon had also helped President Clinton with debate preparation. His brother Michael, the visitor listed in the logs, had been a Biden advisor.

David Ginsberg “is vice president in the Sales and Marketing Group at Intel Corporation” and “[i]n 2012, he took time off to help lead Vice President Joe Biden’s debate preparation team.”

UPDATE: Corrected to note that Michael (not Thomas) Donilon was the visitor on 9-11-12. Go back to the main post by clicking here.