What are some examples in The Duchess of Malfi by John Webster of intersection between the personal and the political?

An important example of the intersection between the personal and the political occurs at the conclusion of the play. Antonio, the Cardinal, the Duke and Bosola lie in "this great ruin," with Bosola the last to die before the entrance of Delio, who enters with Antonio's son. Delio declares Bosola, the Duke and Cardinal, the Duchess and Antonio, in "[b]oth form and matter," melted away as the sun melts snow and frost:

Delio.[They] Leave...

An important example of the intersection between the personal and the political occurs at the conclusion of the play. Antonio, the Cardinal, the Duke and Bosola lie in "this great ruin," with Bosola the last to die before the entrance of Delio, who enters with Antonio's son. Delio declares Bosola, the Duke and Cardinal, the Duchess and Antonio, in "[b]oth form and matter," melted away as the sun melts snow and frost:

Delio. [They] Leave no more fame behind 'em, than should one
Fall in a frost, and leave his print in snow;
As soon as the sun shines, it ever melts,
Both form and matter.

In this example, the political intersects with the personal because the deaths of the Duke and Cardinal were the result of political power struggle, while Antonio's son stands before his father's corpse. To explain, in grasping for the Duchess's land and wealth, the Duke and Cardinal were also grasping for the political power it would deliver to them: The Duke's realm of governance would be increased as would the Cardinal's realm of religious authority. Antonio's son is uninvolved in the political intrigues and the power struggles even though he becomes Duke as a consequence. His interest, a personal one, is in the lives of his mother and father.

Another example occurs during the Duchess's imprisonment. Duke Ferdinand enters with a severed hand, intimating that it is Antonio's hand: 

Ferdinand. I come to seal my peace with you.  Here 's a hand
       Gives her a dead man's hand.
To which you have vow'd much love; the ring upon 't
You gave.

His motivation is a political one: He wants to maneuver the political situation revolving around his sister's wealth, power and marriage to his advantage. To do so, he attacks her psychologically on her personal relationship, hoping "To bring her to despair."