Maria Wyke has written that the play reflects the general anxiety of Elizabethan England over succession of leadership. At the time of its creation and first performance, Queen Elizabeth, a strong ruler, was elderly and had refused to name a successor, leading to worries that a civil war similar to that of Rome might break out after her death.
Critics of Shakespeare's play Julius Caesar differ greatly on their views of Caesar and Brutus. Many have debated whether Caesar or Brutus is the protagonist of the play, because of the title character's death in Act Three, Scene One. But Caesar compares himself to the Northern Star, and perhaps it would be foolish not to consider him as the axial character of the play, around whom the entire story turns. Intertwined in this debate is a smattering of philosophical and psychological ideologies on republicanism and monarchism. One author, Robert C. Reynolds, devotes attention to the names or epithets given to both Brutus and Caesar in his essay "Ironic Epithet in Julius Caesar". This author points out that Casca praises Brutus at face value, but then inadvertently compares him to a disreputable joke of a man by calling him an alchemist, "Oh, he sits high in all the people's hearts,/And that which would appear offence in us/ His countenance, like richest alchemy,/ Will change to virtue and to worthiness" (I.iii.158-60). Reynolds also talks about Caesar and his "Colossus" epithet, which he points out has its obvious connotations of power and manliness, but also lesser known connotations of an outward glorious front and inward chaos. In that essay, the conclusion as to who is the hero or protagonist is ambiguous because of the conceit-like poetic quality of the epithets for Caesar and Brutus.
Myron Taylor, in his essay "Shakespeare's Julius Caesar and the Irony of History", compares the logic and philosophies of Caesar and Brutus. Caesar is deemed an intuitive philosopher who is always right when he goes with his instinct, for instance when he says he fears Cassius as a threat to him before he is killed, his intuition is correct. Brutus is portrayed as a man similar to Caesar, but whose passions lead him to the wrong reasoning, which he realises in the end when he says in V.v.50–51, "Caesar, now be still:/ I kill'd not thee with half so good a will". This interpretation is flawed by the fact it relies on a very odd reading of "good a will" to mean "incorrect judgements" rather than the more intuitive "good intentions."
Joseph W. Houppert acknowledges that some critics have tried to cast Caesar as the protagonist, but that ultimately Brutus is the driving force in the play and is therefore the tragic hero. Brutus attempts to put the republic over his personal relationship with Caesar and kills him. Brutus makes the political mistakes that bring down the republic that his ancestors created. He acts on his passions, does not gather enough evidence to make reasonable decisions and is manipulated by Cassius and the other conspirators.
Traditional readings of the play may maintain that Cassius and the other conspirators are motivated largely by envy and ambition, whereas Brutus is motivated by the demands of honour and patriotism. But one of the central strengths of the play is that it resists categorising its characters as either simple heroes or villains. The political journalist and classicist Garry Wills maintains that "This play is distinctive because it has no villains".
It is a drama famous for the difficulty of deciding which role to emphasise. The characters rotate around each other like the plates of a Calder mobile. Touch one and it affects the position of all the others. Raise one, another sinks. But they keep coming back into a precarious balance.
Wills' contemporary interpretation leans more toward recognition of the conscious, sub-conscious nature of human actions and interactions. In this, the role of Cassius becomes paramount.