In Shakespeare’s play Macbeth, Lady Macbeth is very much involved in the planning of Duncan’s death; indeed, she is the prime mover in the plot. However, later, when Macbeth decides to kill Banquo, Lady Macbeth takes no active role, and indeed Macbeth doesn’t even tell her exactly what he has in mind (3.1.44-46). Several reasons may help to explain why Macbeth does not involve his wife in the plotting of Banquo’s death. Among those reasons are the following:
- By making Macbeth the prime mover in the second death, Shakespeare may have wanted to show how much Macbeth’s moral character has degenerated between Act 1 and Act 3.
- On the other hand, by making Macbeth the prime mover in the second killing, Shakespeare may also have wanted to make Lady Macbeth seem less responsible for the second crime, and thus not darken her moral character even further. If she had participated in the planning of the second murder, she might have seemed an almost Satanic figure; instead, Shakespeare’s presentation of her is far more complex.
- In the scene immediately after Macbeth dispatches two murderers to kill Banquo, Lady Macbeth appears, and it is clear that she is now having second thoughts about the killing of Duncan:
. . . Nought’s had, all’s spent,
Where our desire is got without content:
’Tis safer to be that which we destroy
Than be destruction dwell in dougtful joy. (3.2.4-7)
Perhaps, then, Macbeth did not want to run the risk that his wife might have some qualms about another killing. If she were to have such qualms, she might conceivably have tried to dissuade him from the second murder. After all, she later misses a perfect opportunity to suggest that he kill Banquo (3.2.37-38).
- Perhaps, too, Macbeth did not want to trouble his wife any further than she was already troubled.
- Perhaps Macbeth, having been shamed by his wife into killing Duncan, wants to prove to her now that he can act on his own. This possibility is suggested when he says to her, concerning Banquo’s murder,
Be innocent of the knowledge, dearest chuck,
Till thou applaud the deed. (3.2.45-46)
Such phrasing implies that Macbeth expects his wife to approve of the killing of Banquo and that he even takes a kind of pride in having concocted the plan on his own.