As sagetrieb comments, Julius Caesar contains many excellent examples of rhetoric - examples of how politicians use and abuse speech and words to subtlely manipulate or change meaning and weave it into their own arguments or use the words of their opponents against them. The theme of the play is also very relevant in the cloak and dagger world of politics. The play deals with a world where one man is gaining too much power, and people fear the potential of this, and so try to justify their own ambition and power-hungry nature with all sorts of arguments that obscure their own thirst for power. To be a politician is all about power and ambition, and many people are "sacrificed" or "assassinated" on the journey of one politician's rise to power.
The rhetorical devices used in Brutus’s great speech in Act 3 and in Antony’s speech that follows it offer tricks that we find in many great political speeches. Brutus, for example, repeatedly refers to his own character, wanting to persuade the crowd that because he is an honorable man, what he did was right. He also praises the man he killed, which justifies it in the eyes of the crowd. We see this now when a politician will praise his opponent, even though he has previously devastated him (or her) just previously. “Who is here so vile that will not love his country” he asks (3.2.34). Who could say no? When our politicians began passing legislation after 9/11, a frequent strategy was to suggest that anyone who questioned this legislation was less than patriotic, which is very similar to Brutus’s ploy here. Antony, on the other hand, uses Brutus’s very words in his own speech, yet repeats them ironically and sarcastically, putting Brutus in the wrong even though the crowd had previously believed everything Brutus had said. When Antonysays “And surely Brutus is an honorable man,” his voice drips with sarcasm, so that he does not have to insult his opponent at all—the tone of his voice does it all. We see this in current political debates as candidates repeat the words of their opponent, using them with a different tone to change the meaning. The way all the candidates use the word “change” is an example of this.
Politicians as well as voters should be aware that nothing is new under the sun in terms of moving the masses. False alliances, false piety, effected quotes, sloganeering, simplifying complex issues into trite phrases and appealing to the public as a common man is all present in this play.
Watch for the speeches to the masses to fall into three main categories; fear, pride and guilt. The opening scene includes a rash lecture of the masses using guilt, for example. All great political (and mass advertisements for that matter) use these three great motivators.