Consider Brutuss actions. Is he right to join the conspiracy against Caesar? What are his reasons? Does he join the conspiracy, or is he tricked by Cassius? How do Cassiuss motivations compare to Brutuss? Are they nobler or less noble?
In the play Julius Caesar Brutus, tricked by Cassius, joins the conspiracy against Caesar and kills him. In some ways he was right to join and in others he wasnt.

Brutus and Cassius had different motivation for joining the conspiracy; Brutuss were more political.
Brutus was a loyal friend and joining the conspiracy sort of gave the audience a sense of a disloyal friend. He was wrong to join the conspiracy and shouldnt have killed Caesar. Evan though Brutus had right reason for joining the conspiracy, and killing Caesar, it was not right to turn against a friend.
Envious of Caesars growing popularity, Cassius probed to discover where Brutus deepest sympathies lay. He voiced a concern he had: Caesar was becoming overly ambitious.

Unless something was done to check his fame, he would soon seize all power for himself. This could, effectively, turn the Roman Republic into a dictatorship. Cassius then apprised Brutus of a plot he had hatched: he had a band of other prominent Romans were planning to assassinate Caesar.
Brutus admitted that he shared the same inner concern: I do fear the people choose Caesar for their king.

But still Brutus hesitated to involve himself in such a plot. After all, he dearly loved and admired Caesar. Even so, he couldnt deny that Caesars rapid rise to power constructed a potential threat to the Republic. Brutus promised Cassius that he would consider the matter, but would withhold his decision until the following day.

The dilemma weighed upon Brutus throughout the night; should he aid in the killing of his beloved friend Caesar. Or should he sit by and watch as Caesar destroyed the state?
The plotting band, hoping to gain the support of the highly respected Brutus, paid him an early morning visit. Referring to Caesar as an immortal god, presenting false evidence of his intentions, and playing on Brutus immense love for Rome, Cassius finally prevailed on him to help see the mans death; Brutus agreed to take part in his friends assassination, to think of him as a serpents egg, which, hatched would as his kind, grow mischievous, and kill him in the shell. Assassination- a certain righteous treason- Brutus reluctantly decided, was justified under the circumstances.
Brutus should not have joined the conspiracy.

He joined it for some wrong reasons. Even thou he was very concerned about the Roman Republic, he was still jealous that Caesar had a lot more power then he did. That was a lot of the reason, which was wrong, and not what a noble Roman, and a friend would do.