Hi, I was wondering how Brutus in the Tragedy of Julius Caesar contributed to the downfall of the conspirators. I know one is that he let Antony live and speak at Caesar's funeral, but are there any other mistakes he made? Thank you!

Brutus undoubtedly made a huge mistake in allowing Cassius to talk him into the plot of assassinating Caesar. Cassius is motivated purely by thoughts of personal gain. Brutus, however, has a genuine commitment to the cause of republican liberty and a genuine belief that Caesar's political ambitions represent a threat to that cherished ideal.
However, Brutus is too trusting and too ready to take other people at their word. This tragic flaw is what enables the scheming, devious Cassius to lure him into a plot to murder a man who is supposed to be a close friend. Cassius subtly manipulates Brutus, playing on his sense of honor and nobility to convince him that some of the finest people in Rome are clamoring for him to take over. Brutus is so fixated on what he believes to be his duty that he does not realize that someone else is using him for their own ends.
Brutus's naivety and sense of duty cause him to make another mistake. He blithely assumes that there is no need for the conspirators to pledge an oath of loyalty to each other. This blinds him to the obvious fact that the conspirators have different motives for their participation in the assassination plot, some of which are far from disinterested or noble. Brutus seems to think that showing commitment to the plot is somehow a sufficient sign of loyalty. In this, he is tragically mistaken. Some of the conspirators talk openly about what they are up to; this is how Artemidorus finds out about the plot. He tries to warn Caesar as he is about to the enter the Senate chamber on the Ides of March.
On the field of battle, Brutus makes a huge tactical blunder in marching his troops to Philippi. Cassius is a lot more shrewd in this situation, recognizing that it is much better to allow the enemy to come to them, tiring themselves out in the process:

Tis better that the enemy seek us.
So shall he waste his means, weary his soldiers,
Doing himself offense, whilst we, lying still,
Are full of rest, defense, and nimbleness (act 4, scene 3).

Brutus is so blinded by what he sees as his historical destiny that he is not prepared to listen to reason. Ironically, this is one occasion on which he should have listened to Cassius:


The enemy increaseth every day.
We, at the height, are ready to decline.
There is a tide in the affairs of men,
Which, taken at the flood, leads on to fortune;
Omitted, all the voyage of their life
Is bound in shallows and in miseries.
On such a full sea are we now afloat,
And we must take the current when it serves
Or lose our ventures (act 4, scene 3).



Brutus fervently believes that the tide of history is turning in the conspirators' favor; there must be no retreat and no backing down; now is the right time to strike. He is so intoxicated by this grand vision, however, that he neglects basic military tactics, leading to defeat and, ultimately, his own death.