Sith ’twas my fault to give the people scope, 
’Twould be my tyranny to strike and gall them 
For what I bid them do; for we bid this be done 
When evil deeds have their permissive pass 
And not the punishment. Therefore, indeed, my father, 
I have on Angelo imposed the office, 
Who may in th’ ambush of my name strike home, 
And yet my nature never in the fight 
To do in slander. (1.3.38–47)

The Duke addresses these words to Friar Thomas as he prepares to don the monk’s cowl and so disguise himself as a friar. In a key moment of self-analysis, the Duke reflects on his share of responsibility for the current crime rate in Vienna. He claims that he wanted to give his citizens the requisite “scope” to live out their lives, so he neglected to enforce the existing law against fornication. For this reason, he recognizes that “’twould be my tyranny to strike and gall them” for a crime for which he’d previously given them “their permissive pass.” Even so, the Duke still wants to reassert the law and reestablish the moral order. He’s therefore decided to authorize a deputy to do his dirty work for him. Despite his evident self-awareness, the Duke is also arguably guilty of hypocrisy.

Twice treble shame on Angelo, 
To weed my vice, and let his grow. 
O, what may man within him hide, 
Though angel on the outward side! 
How may likeness made in crimes, 
Making practice on the times, 
To draw with idle spiders’ strings 
Most ponderous and substantial things. 
Craft against vice I must apply. 
With Angelo tonight shall lie 
His old betrothèd but despisèd. 
So disguise shall, by th’ disguisèd, 
Pay with falsehood false exacting 
And perform an old contracting. (3.2.269–82)

The Duke closes act 3 with a soliloquy written, rather unusually, in rhyming couplets of iambic tetrameter. As is well known, Shakespeare tends to write the verse segments of his play in blank verse—that is, in unrhymed iambic pentameter. Though he sometimes includes a rhyming couplet here and there to emphasize a particular point, it’s rare for characters to speak in rhyme for extended periods, and rarer still for them to speak in shortened lines of tetrameter. In this case, the Duke’s soliloquy centers on the shameful Angelo. On the one hand, the Duke’s speech is meant formally to condemn Angelo for his hypocrisy and government overreach. Yet on the other hand, there’s a playful, sing-song quality to the tetrameter rhythm that indicates the Duke feels a little thrill at the idea of staging an elaborate plot designed to teach Angelo a lesson.

If he be like your brother, for his sake 
Is he pardoned; and for your lovely sake, 
Give me your hand and say you will be mine, 
He is my brother too. But fitter time for that. (5.1.562–65)

Near the end of act 5, the Duke finally reveals that Claudio wasn’t executed and that he’s in fact still alive. Immediately after unveiling him, the Duke turns to Isabella and offers this proposal of marriage. But before she can respond, he pauses the proposal with the words, “But fitter time for that.” The “fitter time” comes less than one hundred lines later, when he again turns to Isabella and suggests that they should marry. The play then ends before we hear Isabella’s response, leaving the state of their relationship ambiguous. The ambiguity of these moments has posed a challenge for interpretations of the play on both stage and screen, and directors have tended to go one of ways. In many productions, Isabella silently acquiesces to the Duke’s proposal, and in many others, she silently refuses it. Regardless of how we interpret the ending, it’s important to note that the Duke’s proposal here bears an unsettling resemblance to Angelo’s proposition to Isabella earlier in the play. Both men frame their proposals to Isabella in a way that implicates her relationship of duty to her brother.