Cassius argues against Marc Antony speaking at the funeral. He realizes that Antony can so easily turn the people against the conspirators. Brutus disagrees. He explains to Cassius that he will speak first, and then give permission for Antony to speak. It will appear that Antony is being submissive to the conspirators. This will strengthen the conspirators actions.
Hindsight is twenty, twenty, to borrow a cliche. Cassius was so right. Antony's speech stirs up the crowd to an angry frenzy, an absolute hysteria against the conspirators.
Brutus and the conspirators have to flee for their lives.
Antony's speech has served its purpose. The people are rallied against Brutus and the conspirators. Cassius was wiser than Brutus, but Brutus was in charge.
Brutus has been naive about Julius Caesar’s assassination from the beginning. He believed that killing a friend and leader could be done “nicely.” Cassius was more clear-eyed and ruthless, urging early on to kill Mark Antony, “A shrewd contriver.” Brutus underestimates Antony and professes, “Let us be sacrificers, but not butchers.” He thinks that they should use the minimum violence necessary to overthrow Caesar.
After the murder, Antony’s servant delivers messages of loyalty to Brutus and to Caesar’s memory, requesting a safe meeting with the murderous senators. Brutus takes Antony at his word and refers to him as “a wise and valiant Roman.” He thinks Antony would be a great ally, but Cassius is skeptical. When Antony arrives, he suggests they kill him then and there; Brutus refuses. Antony shakes their bloody hands but then mourns over Caesar’s body, offering him all manner of praise. This worries Cassius more than Brutus.
Antony says that all he wants is to understand why they killed Caesar and to have an opportunity to speak at Caesar’s funeral. Cassius argues against this, asking Brutus, “Know you how much the people may be moved / By that which he will utter?” Brutus claims that they will appear to be generous by giving Caesar “all true rites and lawful ceremonies.” He will speak first and direct Antony to speak well of Caesar but not poorly of the conspirators.
Cassius is completely right. In spite of Brutus’s compelling speech and strict instructions, Antony quickly turns the crowd against the conspirators. Brutus’s motives were noble and had some logic, but he could never truly reconcile with the truth that an assassination is a brutal act that requires detachment.