Hamlet ’s major antagonist is a shrewd, lustful, conniving king who contrasts sharply with the other male characters in the play. Whereas most of the other important men in Hamlet are preoccupied with ideas of justice, revenge, and moral balance, Claudius is bent upon maintaining his own power. The old King Hamlet was apparently a stern warrior, but Claudius is a corrupt politician whose main weapon is his ability to manipulate others through his skillful use of language. Claudius’s speech is compared to poison being poured in the ear—the method he used to murder Hamlet’s father. Claudius’s love for Gertrude may be sincere, but it also seems likely that he married her as a strategic move, to help him win the throne away from Hamlet after the death of the king. As the play progresses, Claudius’s mounting fear of Hamlet’s insanity leads him to ever greater self-preoccupation; when Gertrude tells him that Hamlet has killed Polonius, Claudius does not remark that Gertrude might have been in danger, but only that he would have been in danger had he been in the room. He tells Laertes the same thing as he attempts to soothe the young man’s anger after his father’s death. Claudius is ultimately too crafty for his own good. In Act V, scene ii, rather than allowing Laertes only two methods of killing Hamlet, the sharpened sword and the poison on the blade, Claudius insists on a third, the poisoned goblet. When Gertrude inadvertently drinks the poison and dies, Hamlet is at last able to bring himself to kill Claudius, and the king is felled by his own cowardly machination.
During "The Mousetrap" Shakespeare has two plays going at once. The outer play which has an animated Hamlet doing his best to hold in his excitement and the inner play of clueless actors. The inner play containing its own tensions, is the impetus for much of the tension in the outer play. From earlier in this scene Hamlet expressed his dislike of Dumb-shows. And yet the players open the Mousetrap with a dumb-show that threatens to spring the trap. After the dumb-show we are left with the question of whether the king did or didn’t note the “argument of the play.”
Aside from the dumb show the inner play is really two plays in one. The first we might properly call “The Mousetrap”. Observe later in Gertrude’s closet where Hamlet suggests the pet name of “mouse” for Gertrude. The Mousetrap’s focus is on Gertrude. The bearing of souls between the Player Queen and the Player King is Hamlet’s attempt to catch the conscience of Gertrude. Did she have any hand at all in the plotting and killing of King Hamlet? All we get from Gertrude is that the lady protests too much.
On to scene two the “Murder of Gonzago”. This is directed at Claudius and where both Shakespeare and Hamlet ratchet up the tensions. Hamlet’s earlier admonishment that the players will “tell all” would be better observed by Hamlet at this point. Hamlet is the one who should guard his words. As Ophelia tells him, “You are as good as a chorus....” Hamlet’s first slip “poison in jest,” unduly calls attention to the dumb-show poisoning. His next slip is identifying Lucianus as “nephew to the king.” It is not pertinent to the story but it does make Claudius and others aware of a parallel between Hamlet and Lucianus. So when Claudius does exit the play is it his guilt, or the overt threat of a nephew killing the king that does so? Or perhaps it is seen as a tasteless prank.
The result is that Hamlet is convinced that the king is guilty. This brings about the death of Polonius and sets in motion the Laertes revenge subplot. As for Claudius, he sees Hamlet as a danger and doubles his efforts to be rid of him.