Well, it's been rumored that Haig was "Deep Throat", the informant that helped toppled Nixon. Ford replaced him almost immediately with Rumsfeld, who also brought in Cheney to the Ford transition team. Both were rising stars in the Nixon administration.
Just guessing...
You must have missed this:
But, in 2005, it was revealed in that W. Mark Felt, the associate director of the FBI, was Woodward and Bernstein's source. Furthermore, Haig was known to have been out of the country during some of the meetings between "Deep Throat" and the reporters.