The effects of power are seen through the tragedy of Julius Caesar in several different ways. Most importantly, the way power is perceived is what leads to the killing of Caesar. Cassius believes that the power has gone to Caesar's head and that he is going to become a tyrant if he alone is in charge of Rome. Brutus agrees to do what is necessary for the good of Rome and helps the conspirators enact their plan. In doing this, they are feeling the effects of power themselves. They have taken it upon themselves to "fix" the problem with Rome (Caesar), and this shows that they feel a power within themselves that gives them that right.
Antony feels the effects of power after Caesar is killed. He learns how to manipulate Brutus into letting him speak at Caesar's funeral, and gains power from the crowd's reactions. Using that, he ends up defeating Cassius and Brutus' armies, who crumble under the effects of power that are put on them after killing Caesar.
