Explain the irony in Iago's discussion with Othello after Iago has just left Roderigo at Brabantio's house.

Iago acts as if he is on Othello's side, even though he has expressed he cannot say anything negative about Othello.  He also says that he believes that they will not "punish" Othello for marrying Desdemona because Othello is needed in the war against Cyprus.  Yet Brabantio is on the hunt for his daughter and Othello, but Iago is somewhat trying to play as if he is not on either side.