The next person that Iago manipulates is Cassio; Lieutenant to Othello. Iago despises him because he thinks that he should have the rightful post as Lieutenant. At the end of the scene when Iago is with Roderigo he plots against Cassio, he wants to get him closer to Desdemona so he can make the excuse that Desdemona is having an affair with Cassio. This means that Cassio would be sacked as Lieutenant so Iago could take his place.
This all starts when Iago and Cassio are in the soldier's mess and Iago starts chatting boyishly to Cassio in a civilised conversation. "She is sport for Jove." in a very casual way Iago starts to talk about Desdemona. If this was in a theatre, you could imagine Iago lying down in a provocative way, this way Iago can force Cassio into admitting that Desdemona is good looking and leads him on, "and she is the most exquisite lady". Again, Iago is manipulating Cassio's mind and he is completely oblivious to what Iago is planning. He asks Iago to have a drink of wine, "Come Lieutenant, I have a stoop of wine...would fain have a measure." The atmosphere is still calm and relaxed but you can observe that Iago is still plotting and is vaguely forceful. Cassio still has no idea what Iago is doing which means that Iago can use emotional blackmail to compel him to have a drink. Nevertheless, Cassio says no, "I have very poor and unhappy brains for drinking." Cassio declines because he knows from experience that aggressiveness will take over if he is given too much. Iago knows this and his plan begins to unfold. Cassio goes out but comes back in a few minutes later accompanied by members of the watch. While Cassio is out, "Honest" Iago speaks to the audience "If I can but fasten but on cup upon him...he'll be as full of quarrel...as my Mistress' dog." By Iago comparing Cassio with his wife's dog, he is giving a good image of Cassio and you can see what he wants to do. When Cassio has returned from outside Iago starts a song as the men have been drinking and Cassio could not turn down the offer. "The canakin clink, clink" This is sung to get the men into a good mood. The effect of the song makes the men happy but Iago sings it because he wants to make Cassio insecure and over excited so he becomes aggressive.
A fight is started between Montano and Cassio. Othello comes and Cassio is told off. Iago now pretends that he has nothing to do with it, Othello believes him but only because Iago has a false reputation of being honest. Iago's plan works and Cassio gets the main blame. The way he does this is to suck up to Othello pretending that he had nothing to do with it and "honest" Iago is right after all. "I'd rather have the tongue cut from my mouth than to do offence to Michael Cassio." This is untrue and because Othello trusts Iago, he believes it. Iago pretends he was not involved and he had only come into the room because he had heard "the clink, and fall of swords". Here Iago uses a clever pun, linked to the song before Othello had come in. Iago uses "clink" in the song to stress that it was about drinking and uses it when he is talking to Othello to imply drinking and violence. "But men are men." There is a clear change in tone about Iago's voice and he says it in appealing way to again try to play up to Othello. The reply is "I know Iago, thy.... love doth mince this matter, making it light to Cassio". This makes Iago even more secure because he knows that Othello does not really know what is going on.
Iago also works on Othello and drives him into killing Desdemona. "I like not that", Iago makes subtle comments about the two of them when Othello is in the room, and in this way makes himself nobler but Cassio less at the same time. He then goes on to say, "I know not what" because he wants Othello to know what is going on between them but he does not want to say it literally just in a more delicate way. Then Iago accuses Cassio of "stealing away" Desdemona. There is a double meaning in this sentence, Iago wants Othello to think that Cassio would like to steal his wife, just as Desdemona will ask Othello to take Cassio back once he has been sacked as Lieutenant. In this scene, Iago hammers down on sentences and phrases that put points across which are not necessarily true. Iago carries on, "suitor here"; this is referring to Cassio and Desdemona again. There is another double meaning here, "Suitor" means friend or lover and implies that someone has feelings for her. However, Othello would think that Iago meant Desdemona has a friend so this proves that Iago is being very clever and always knows what to say.
The tactic that Iago uses does not get him very far so he tries a new one "Indeed...Honest, my Lord...Think my Lord". Instead of dropping points, Iago repeats what Othello says through innocent rhetorical questions, which emphasise the points that Othello is saying. Iago hopes this will make him anxious so Iago can tell him about Cassio and Desdemona without putting it blankly. After a while this seems to work, Othello then says "Monster in thy thoughts too hideous to be shown". This means he sees Iago is holding something back; it has an aura of sincerity. Iago feels that Othello has cracked the point to early and to get him off the subject, takes a big risk and says, "I dare be sworn, I think that he is honest." This is sport for Iago and gives him a reward (money from Roderigo), when it is all over he will have nothing to do. Perhaps he does it so he does not have to be reminded of Emilia and Othello, he is driven because of his own jealousy and problems. Iago then starts to dig up Othello's past by referring to slavery all the time "Slaves are free". This uproots Othello's dignity and heritage and opens him up for more verbal attack. "As where's that Palace, whereinto foul things, sometimes intrude not?" This is said by Iago to prove the point to Othello that even the most precious things can be taken away and have a centre of sin. Then Iago tries to convince Othello that he is trying to give him the best advice even if he has flaws in him, "It is my nature's plague...to shape faults that are not". If you admit to a flaw then it proves you are an honest person, it also makes Othello endeavour more into Iago's thoughts. He then uses "I see you are moved" to try to force Othello to admit that he is wrong. Whilst Othello is in denial in the back of his head, he is thinking about what would happen if Iago was wrong, Othello is hesitant. "I do not think but Desdemona is honest" there is still an element of doubt as he uses the word "think". Iago can then pick this up, "and long live you think so". Here Iago takes Othello's words and manipulates them into his own forcing Othello to doubt himself even more. At the end of the play Othello starts to believe Iago and suffocates Desdemona and then commits suicide when he realises he has been set up.
Iago's motive is that he was jealous of Cassio because Othello had chosen him as Lieutenant. He wanted to get rid of Cassio by framing him and accusing him of having an affair with Desdemona. Iago wanted to get Othello angry and fore him to dump Desdemona so, the plan would work. This way it would seem that she had left Othello for Cassio. It only starts to wrong when Othello over reacts and kills Desdemona. Shakespeare's characters have very deep emotions and some of them even have hidden morals. Othello a black slave most of his life has the image of the odd one out in the predominantly white community of that time. Iago renound for his modesty and honesty but it is only in the play that you see his true side. From the characters and the methods used by Shakespeare, you can truly see the acidity of the time and how close his work represents real life.
