In what sense is Brutus in conflict with himself?

We can see much of Brutus's inner conflict in Act one. In scene 2 Brutus tells Cassius that he has been quiet because he has been plagued with conflicting thoughts. Brutus is close to Caesar; he loves Caesar as a friend but not the leader of Rome. Brutus fears Caesar's power is too great and that he will ruin Rome with absolute unchecked power. Brutus feels this treason in himself and is conflicted by it. Is Rome, as a republic, more important than his friendship and loyalty to Caesar?