Social science shows that power—even in small doses—triples our likelihood to be self centered, and therefore blind to others' points of view.
Imagine what large doses do.
So if you want to persuade people in power of your opinion, it's essential that you learn how to empathize; or, as Daniel Pink says, improve your "attunement."
Philosopher Blaise Pascal explained why succinctly in 1670:
"When we wish to correct with advantage, and to show another that he errs, we must notice from what side he views the matter, for on that side it is usually true, and admit that truth to him, but reveal to him the side on which it is false. He is satisfied with that, for he sees that he was not mistaken, and that he only failed to see all sides."