I have a manager who is known for bullying. Our department must have had the highest staff turnover in our company! Unfortunately, the longer-term members had an attitude of, "Just get your head down and get on with it"... and it carried on until I got called into a private meeting with someone more senior. That person believed in me, supported me through the grievance process, got HR involved, etc. Unfortunately, the manager got off scot-free that time, because nobody else would back me up. However, it's much better as he has to be on his best behaviour. Occasionally, it starts to slip, and a quick word with his new manager sorts it out very quickly. The huge personality change has encouraged others to start speaking up; I got told, "If I knew what a difference it would make, I'd have said something sooner!". We are sometimes called into meetings with other senior people to report other issues. I assume that there is a case being built in the background for his unceremonious departure.
In his experience, I think that the power went to his head. In his head, he is always right, and anybody else's opinion is wrong. Left unchecked for too long, in a fairly isolated department, he could fly off the handle and, although there was obviously an issue somewhere (i.e. staff leaving, mental health issues), nobody outside of our department knew exactly what was going on.
The one thing that encouraged me to keep pushing for him to stop was the thought that I didn't want anyone else to go through the same experiences. I recently read in a book that your silence gives permission for the bully to carry on, and on reflection, I think that is true. Thus, I will not stay silent and put up with bullying in the workplace! However, we still pray for the manager's demise, as he doesn't seem to plan on retiring any time soon.