What distinguishes humans from other animals, of course, is speech and the consequences of speech.
It is not merely thought, because other animals are capable of learning and behavior that most of us classify as intelligent.
But what is particularly human, and what gave rise to speech in the first space, is the concept of right and wrong.
I am not suggesting any absolute standard of right and wrong; different humans will always disagree about points of morality. But it is very important that humans are capable of judging themselves and others, and they do talk about it. Early humans needed speech to express their moral judgments to others.
There is a great risk of too much power: that these powerful persons will lose their morality, and come to believe that power justifies itself. Such amoral leadership is a risk to humanity; if necessary the people must rise up in opposition to power exercised without moral judgment.
We are fortunate to live in a world where the moral accountability of powerful leaders is a widely accepted political principle. If the people are vigilant in protesting what they see as immoral abuses of power, those leaders will feel constrained to behave with a higher level of morality.