Thank you for the opportunity to help you with your question!
It is true all leaders need some degree of power to be effective. A leader who has no power can never have enough confidence to make decisions.
If a leader is rendered powerless chances are the leader will be overthrown and therefore that simply means that the leader was overthrown due to lack of power. Too much power is however too much. This may lead to dictatorship in most cases and dictatorship is not leadership. It is more of ruling.
For instance, in a country like Uganda; the president is the sole and the final decision maker to some extent. This has caused Uganda to stick to old ideologies and policies through since independence.
Please let me know if you need any clarification or modification. I'm always happy to answer your questions.
Thank you for offering me this opportunity.
Kindly contact me if you need further clarification