Does effective leaders also mean ethical leaders?

Question? Does effective leadership also mean ethical leaders? When we research the topic of leaderships, we would find that many leaders that were very successful in their career, often had made some unethical discussions throughout their profession. I am not talking about an Enron or WorldCom, which was obviously an unethical sinkhole. I am talking about how our leaders or we transmit sensitive information. Our actions and choices in the workplace, which may seemed tamed at the time of excitation but eventually evolved into a mountain of ethical proportion.