What new perspectives (that we have not seen in the play thus far) on political intrigue and ambition do Lady Macduff and her son provide? story of

The murder
of 's family in Act 4.2 of Shakespeare's reveals new heights of 's
ambition, and of what he is politically willing to do to maintain power.

Perhaps I should say "new lows" of ambition and political intrigue are revealed.  The
killing of Macduff's family serves no strategic purpose.  It is petty and motivated only by
Macbeth's being insulted by...