The missing emails. 
The post-9/11 theft of presidential records from the public. 
Now this :
A lawyer for Vice President Dick Cheney told the Secret Service in September to eliminate data on who visited Cheney at his official residence, a newly disclosed letter states. The Sept. 13, 2006, letter from Cheney's lawyer says logs for Cheney's residence on the grounds of the Naval Observatory are subject to the Presidential Records Act.
Such a designation prevents the public from learning who visited the vice president.
On a related note, concerning the second link above, a Washington Post story on the Bush executive order extending presidents' power under that same Presidential Records Act to keep historical documents from the public, provides an outstanding object lesson in Nixonian techniques of spin. "The majority of former presidents have released virtually all of their records. This executive order does nothing to change that," a White House aide is quoted. So if Bush, say, holds back virtually all of its records, that aide is still telling "the truth."