The best recent example I have is the resignation of Secretary of Defense Donald Rumsfeld the day after the Democrats won control of Congress, Wednesday November 8th 2006.
Rummy knew Congress, having been a congressman for eight years. He had been in Washington for over forty years so he really knew Congress and politics.
What Rummy knew is very simple: The Democratic Congress, just elected, hated him for his role in starting and running the Iraq war. With a Democratic majority Congress could harass him as Secretary of Defense mercilessly until he would have to spend so much time before hostile Congressional committees that he could never get a day's work done.
He quit and disappeared from Congressional radar. Smart man. Super smart man.
With the return of a Republican President and Congress we will see Rummy again as a grand old man. A wise man.