The overriding flaw that turns Macbeth from a decorated military commander, loyal to the King, into a murderous usurper of the crown is ambition. As Shakespeare informs us, Macbeth’s ambition is so “vaulting” that it “overleaps” him. However, even though ambition drives Macbeth, his tragedy comes about from two other forces that misguide him and add fuel to his already burning ambitions. This is what makes his downfall tragic, he overrides his instincts and principles in favor of murder and power. The first of these influences is the Machiavelli-like encouragement of Lady Macbeth, who spurs Macbeth to do the deed and “screw [his] courage to the sticking place” when Macbeth is most wavering in action (1052). Macbeth does not become controlled by ambition until late in the play. He stands in awe of Lady Macbeth’s lack of emotion and cold-blooded calculation after he sees Banquo’s ghost: “You make me strange/Even to the disposition I owe, / When now I think you can behold such / And keep the natural rub of your cheeks, / When mine are blanched with fear” (1059). Thus, Macbeth’s ambition is fueled by Lady Macbeth’s influence.
The second influence that dangerously emboldens Macbeth’s ambition is his misreading of the prophecies of the three witches, which he interprets as a sign of invincibility when actually they are harbingers of his doom. The witches show Macbeth three portents; an armed hand, a bloodied child, and a child crowned with a tree in his hand. Macbeth’s interpretation of these portents is very significant to his downfall, because it is the fuel that ignites his ambition into a roaring blaze. The witches tell Macbeth “no man born of woman will harm him” and he will never be vanquished “until / Great Britain wood to high Dusinane hill /Shall come against him” (1061).
At this point Macbeth becomes blinded by ambition, power-hungry, and overc