The Bush administration will never allow the truth about OKC to be uncovered, because it would impact the GOP as much as the Democrats.
The president did nothing to delay the execution of McVeigh. As I recall, McVeigh's lawyer was pushing for a delay and the president had the authority to delay, but didn't. After 9/11, I think it would have been prudent for the president to keep McVeigh alive and let his lawyers fish through the FBI deception.