Science finds power magnifies personality. It could magnify Trump’s. - Vox

Power gets into our heads... give us confidence to indulge in our base urges. It can make us less empathetic, more likely to see our own success in a positive light and harshly condemn failures in others...power is only likely to magnify the negative characteristics in a man like Trump... “power simply brings our true nature out into the open”...
when a person is given more power, they become even more like themselves... behave more consistently... The context of the situation doesn’t get in the way of the self....
Power magnifies your personality traits... we might want to find [candidates] who have balanced, moderate personality traits...
Power ... also subtly influences all of us to become a bit more selfish... less empathetic, and are literally less able to read emotion in the eyes of others... less likely to take the perspective of others...Powerful people are more self-serving... more prone to hypocrisy... it also increases feelings of responsibility.