誰給它權力? - No one gives him power. He ASSUMES POWER.

Only people who do not have power would ask question like this.  :)

The governed: Hey, Dude! Why can you have the power OVER ME? Who gives you the right to do so?

The governing: Because if you don't do what I tell you, I will k**ill you or put you to jail.  I have guns and the well fed bodies that hold those guns.  You don't! So suck your thumb and obey.

THAT IS POWER!