Perhaps the best thing you can say about Donald Rumsfeld is that Henry Kissinger hated him. The antagonism dated back to the Ford Presidency, when Rumsfeld undermined Henry K’s freelance diplomacy and covertly sought to destroy Kissinger’s détente project.
Rumsfeld (“Rummy to his friends”–though he confessed to Nixon that he never drank with reporters or Secret Service agents) wasn’t all that close to George HW Bush, either. Recall that Rumsfeld launched a presidential bid against Poppy in 1988. Unable to raise much cash, Rumsfeld backed out and promptly endorsed Bush’s arch-rival Bob Dole.