Discuss the theme of loyalty vs. Disloyalty as you see it in "Hamlet". There is a group of literary critics who argue that Shakespeare’s "Hamlet"...

Loyalty, although typically considered a good thing, actually does a lot of damage in the play "Hamlet."  It is loyalty to their fathers that drive Hamlet and Laertes to revenge--without those avowals of avenging the deaths of their fathers, which can be tied directly back to their loyalty to their fathers and their family name, then all of the deaths in the play would not have occurred.  Then, consider the interesting characters of Rosencrantz and Guildenstern--here are two buds of Hamlet's, who are supposed to be loyal to him.  However, they switch their loyalties to the king, and agree to spy on Hamlet, and then, to "dispatch" of him.  Loyalty to the king, (which in turn shows disloyalty to Hamlet) drives them to betrayal of a friendship and trust, and potentially to murder.  It is Hamlet's discovery of their murderous summons that prompts him to kill them.  He feels betrayed by their lack of loyalty to him, in the name of obedience to the powerful king.

Disloyalty also plays a role.  Consider how Gertrude's disloyalty to the memory of her first husband upsets Hamlet so much; his anger over her "o'er hasty marriage" to Claudius is one thing that makes Hamlet more driven to kill Claudius.  It is what drives him to his mother's chambers to chew her out for her "incestuous" deeds; this leads to the death of Polonius.  Then, Hamlet's apparent disloyalty to Ophelia prompts her to return his love tokens and a rather bitter break-up between the two.  This inevitably leads to part of her breakdown later on in the play.  Gertrude's disloyalty leads to Hamlet's harsh opinion of all women, and thus his ranting against Ophelia at their meeting.

Those are just a few thoughts on the roles that disloyalty and loyalty play in "Hamlet," and I hope that they helped; good luck!