Final answer:
The crowd in 'Julius Caesar' begins to accept the argument that the conspirators were justified in murdering Caesar based on Brutus's persuasive speech.
Step-by-step explanation:
The immediate effect of Brutus's speech on the crowd in Julius Caesar, Act 3, Scene 2, is that the crowd begins to accept the argument that the conspirators were obligated to murder Caesar. This acceptance is due to Brutus's persuasive explanation that his actions were driven by his love for Rome and his desire to prevent Caesar's ambition from turning the citizens into slaves. By expressing his personal grief for the loss of Caesar while also highlighting the threat posed by Caesar's ambition, Brutus successfully convinces the crowd that the assassination was a necessary act for the good of Rome.