The words in the brackets are telling the actors what to physically do, meaning it would be a stage direction.
It isn't dialogue because that is a conversation between two people.
It isn't dialect because that is how a person speaks. There is no speaking in the brackets.
It isn't narration because it isn't spoken allowed for the audience.
It isn't a description because that is too broad a term more often used for emotions.
Answer:
Alexander Hamilton was the leader of the Federalist party.
Hope it helps!
