To what extent do you think is Iago responsible for Othello's undoing?

Of all Shakespearean tragedies, Othello is perhaps the most painfully exciting and the most terrible. How we interpret this great tragedy is significant: it is not only the focus of the drama, but also the main argument of the text. There are many aspects in which readers must evince their own judgement to decide who should be accounted responsible to the terrible events. I have't! It is engend'red! Hell and night <Tab/&…

…would conflict with our sense of moral justice. If Iago is essential to the catastrophe, but no the only one responsible, then the text is far richer. Sure enough, the readers do feel for Othello's well intentions and unjust consequences, it is also self-delusion and his forfeiting of control over his passion that opened the way for Iago's villainy to seep through. Thus Iago cannot be held responsible for the full extent of the tragedy.