Othello: Iago's Motives

One of Iago’s primary motives for attempting to sabotage Othello is that Iago is frustrated that Othello has made Cassio his lieutenant instead of Iago.  He notes that Cassio is “a great arithmetician” but that he has "never set a squadron in the field” (I.i.20, 23).  Although Cassio is clever, he has far less experience than Iago, so Iago is especially frustrated with Othello’s choice.  He wants to be Othello’s lieutenant, but Othello chooses someone else, so Iago feels offended.  Therefore, he seeks to undermine Othello in order to wreak his revenge.

In addition to Iago’s jealousy of Cassio’s appointment, Iago is also jealous of Othello himself.  Othello is the commander of the mighty Venetian military, a highly coveted post in the most powerful military in Europe.  Iago would love the opportunity to hold this position.  Iago and Othello are like in that they both have extensive military experience; the intellectual Cassio serves as a foil to Iago in this way, which enhances the comparison between Iago and Othello.  Since Iago and Othello are similar in this way, have fought in battle together, and play similar roles in society, either one of them could hold the post.  Othello has earned it through his merit, but Iago feels entitled to it through his aristocratic origins, and may subconsciously wish that he could overthrow Othello and claim the post as his own.