With Lady Macbeth, it is the case of Adam giving Eve the apple, instead of the other way around. With his letter, Macbeth plants in her visions of grandeur, which ultimately leads to her downfall as well as his. Macbeth's own impressionability and delusions infect his wife and she quickly becomes the main motivator of "their" actions. No longer "ignorant of what greatness is promised" her, Lady Macbeth is the engine fueling her husband's ill-fated siege of Scotland's throne. She realizes that he hasn't the stomach for lechery and treason and uses her womanly charms to thwart his hesitations. For all intents and purposes, she wears the pants in the relationship; she has the plans, she's got the backbone, and her words have more weight that do his.
"We fail! But screw your courage to the sticking place, and we"ll not fail- This was my favorite line of the play. Her language is strong and her intentions are unyielding. She refuses to entertain Macbeth's wavering conscience, blinded by her own desire for power. I think maybe in her mind, the throne is actually secondary. Her power over Macbeth is sufficient and sharing a bed with the crowned king is merely an offshoot of that. As part of her manipulation, Lady Macbeth questions the manhood of her husband, implying that he must murder Duncan in order to prove himself a man. Even after the deed is done, she is disgusted by his sensitivity and remorse. She decides to take matters into her own hands and replaces the bloody daggers to complete the murderous deceit. .
Her public performance is flawless, unlike Macbeth, who shows outward signs of weakness and even madness in front of Duncan at the feast and in the presence of the rest of court at the dinner table in a later scene. Lady Macbeth plays the perfect hostess and the perfect lady. "Your majesty loads our house, for those of old, and the late dignities heap"d up to them- She switches her demeanor quickly and conspires with Macbeth outside the dinner hall.
