Othello is the story of a noble military general who has enjoyed many successes on the battlefield, but because of mistakes of judgment and his outsider status in his society, sabotages his most intimate relationship and himself. The play begins on the grand scale of a military romance unfolding on the Mediterranean Sea. However, the action of the drama shrinks to the claustrophobic ending in the cramped bedroom where Othello kills himself after smothering his innocent wife. The play moves from vast exteriors that provide a backdrop for Othello’s heroism to interior spaces that offer—both literally and figuratively—no room to breathe. The play’s constricting trajectory suggests that negative emotions like jealousy put an emotional chokehold on a person, strangling their ability to think clearly and thus preventing them from acting reasonably. It also contrasts the arenas in which Othello is confident and powerful, such as the exterior world of battle, with the domestic spaces in which he is less secure, and able to be easily manipulated.

The incident that sets the protagonist and antagonist on a collision course occurs before the play begins, when Othello chooses Cassio as lieutenant. In being passed over for promotion, Iago feels cast aside and left to fill the role of “ancient” (i.e., ensign), a military position that ranks at the very bottom of all commissioned officers. Though angry with Othello’s choice, Iago feels equally upset that the coveted job went to Cassio, who Iago considers less qualified than he is. He also later reveals that he believes Cassio might have slept with his wife (in addition to suspecting Othello slept with her): “For I fear Cassio with my night-cap too.” (II.i.) Iago feels doubly degraded: a promotion he believes was rightfully his went to another man, and both men responsible for the slight – Othello and Cassio – may be sleeping with his wife. At this point, the audience’s sympathies are aligned with Iago, as we haven’t yet seen Othello, and Iago does have just cause for his grievances.

The tension of the play rises once the audience meets Othello and realizes how disastrous Iago’s plan will be. Othello and Desdemona’s declarations of love for each other, and Desdemona’s willingness to be disowned by her father in order to be with Othello, raise the stakes for the couple, and shifts the audience to Othello’s side. By contrasting Othello, Desdemona, and Cassio’s virtuous natures with Iago’s lies, the play heightens the tension between the truth and deception. With everyone in the play subject to Iago’s scheming, the audience becomes his silent co-conspirator as he unveils his plans in a series of asides. As Iago easily succeeds in his plot to get Cassio drunk, incite him to fight Roderigo, and convince Othello to fire him – all the while acting as though he loves Cassio – we see what a skilled manipulator he is. Iago’s scheming, cynical nature is starkly contrasted with the rest of the characters in the play, who are all undone by their own trusting, honest natures and their inability to see through Iago’s deceptions.

The conflicting forces of good, as represented by Othello, and evil, as represented by Iago, come into direct contact at the end of Act III, scene iii, when Othello kneels with Iago and pledges his unswerving desire to take revenge on those who have cuckolded him. Unlike many Shakespearean tragedies where the protagonist confronts the antagonist at the play’s climax, Othello expresses his absolute trust in Iago by appointing him his new lieutenant. Othello’s misplacement of trust, and blindness to Iago’s true motivations, increases the tension further, as the audience wonders when, if ever, Othello will see the truth about his supposed friend. As Othello becomes increasingly deranged with jealousy, and refuses to listen to Desdemona’s protestations of her innocence, he becomes less a protagonist, and starts to figure more as a second antagonist, acting in league with Iago. From this point on, no matter what Desdemona does, it only proves her guilt in Othello’s eyes.

In the play’s remaining two acts, Iago’s treacherous plot unfolds with a brutal inevitability. Othello shifts from believing Desdemona could never betray him, to demanding proof of her infidelity so he can feel justified in killing her. When Iago suggests Othello strangle Desdemona in the bed in which she was allegedly unfaithful, Othello says “Good, good, the justice of it pleases!” (IV.i). Othello still loves his wife passionately, but rather than considering her virtues as arguments against Iago’s accusations, instead sees them as reasons to be all the more upset by her alleged infidelity: “O Iago, the pity of it, Iago!” (IV.i) Deranged with jealousy, Othello conspires with Iago to murder Cassio and devises his plan to kill Desdemona. Either his wife has been unfaithful and is lying to him, or his beloved, “honest” friend Iago has been lying to him. Only after he kills Desdemona does Othello discover he believed the wrong person. When he at last realizes his error, he kills himself, rather than live in a world where honor and honesty have no value.