How is the issue of power in Hamlet similar to Frankenstein?

In the words of Lord Acton, power tends to corrupt, and absolute power corrupts absolutely. One glance at the world shows us that this is as true today as it ever was. The more that power is concentrated in the hands of a small, unrepresentative elite, the more it corrupts, not just those who hold that power but also the people they control.

In Hamlet, we see a prime illustration of this point after Claudius murders his way to the throne of Denmark after killing his own brother, Hamlet's father. Since Claudius took over, the whole atmosphere of life in Denmark has changed, and not for the better.

The very air seems thick with corruption; it constitutes, in the words of Hamlet, “a foul and pestilent congregation of vapors”. The moral life of the nation has been corrupted by Claudius's usurpation of kingly power. In vowing revenge upon his wicked uncle/stepfather, Hamlet is embarking upon a moral crusade as much as anything, an attempt to restore some much-needed morality to the kingdom.

In Frankenstein, Victor also has absolute power, albeit not of a political kind. He has the power, derived from his remarkable scientific genius, to create his own race of monsters. But his absolute power corrupts his soul as well as that of the Monster he creates. The Monster has turned out the way he has because of Victor; his very existence is a living, breathing testament to a systematic abuse of power by someone who really ought to know better.

How is justice in Shakespeare's Hamlet similar to that in Shelley's Frankenstein?

According to the theory of natural law, there is a timeless moral standard that applies equally to everyone in all circumstances, irrespective of cultural and historical differences. On this reading, justice is not a man-made concept but an absolute standard laid down by God. As we are all God's creatures, we have a duty to obey it at all times.

The notion of a higher law is much in evidence in both Hamlet and Frankenstein. In Shakespeare's play, it is the title character who grasps more than anyone else the importance of the concept of cosmic justice. Hamlet knows that Claudius, by murdering old King Hamlet, has violated God's law and must be punished for his transgressions.

But as Claudius is the King of Denmark, and therefore in charge of the criminal justice system, he cannot be punished according to merely human notions of justice. God's law must be upheld, and Hamlet, in his roundabout way, is determined to be the one to do it.

In Frankenstein, the deficiencies of human justice are also on display. Poor Justine has been executed for the murder of Frankenstein's brother William, despite the fact that she's completely innocent of any crime. (It was, of course, the creature who killed William.) The judge who sent Justine to the gallows most probably thought that he was doing the right thing given all the available evidence. But in actual fact, he was just showing the inadequacy of human justice by comparison with the timeless standard derived from divine law.

Frankenstein is acutely aware of this and is wracked by guilt over Justine's tragic fate. But there's absolutely nothing he can do about it. Frankenstein may well have played God in creating his creature, but he cannot take the place of the Almighty in righting this terrible wrong.