According to David Ignatius of the Washington Post, Secretary Rumsfeld was scheduled for firing in the summer of 2006:
Oddly enough, it was the generals who helped keep Rumsfeld in his job. The White House had decided in the spring that it was time to make a change at the Pentagon, and officials were steeling themselves to break the news to Rumsfeld when the "generals' revolt" erupted on newspaper op-ed pages, with former officers lining up to denounce their ex-boss. The White House decided it couldn't appear to bow to pressure and retreated.
Isn't that funny? The ex-generals, by calling for Rumsfeld's resignation, kept it from happening. The White House, reversing its intuition to cut Rummy loose, kept him in order to look strong. The result: they deprived themselves of a smart political move that could have potentially saved the House and Senate from the Democrats in November.
What followed? What they wouldn't do in June, they were forced to do November 8.