Why can Hamlet be so ruthless with the likes of Polonius, Guildenstern and Rosencrantz yet seem so incapable of acting against Claudius?
Hamlet is very ruthless with the likes of Polonius, Guildernstern and Rosencrantz. For example. he sets Guildernstern and Rosencrantz up to be executed, claiming that they deserved it. He kills Polonius and seems to have no sorrow afterwards, also claiming he deserved it since he was spying on him.
Hamlet seems incapable of acting against Claudius, however. He takes 2 months to finally kill him, passing up many opportunities along the way, continiung to make up excuses for not killing him. Why is that?
It has been said that Hamlet thinks too much. That, according to Coleridge and others, is his tragic flaw. If he acts on impulse he can act decisively, but when he thinks about doing something he gets lost in speculations and loses the all-important feeling he needs to commit murder. Macbeth says: "The flighty purpose never is o'ertook, unless the deed go with it."
With Polonius, Hamlet has his mother crying for help in front of him and Polonius crying for help behind the tapestry. He thinks it is a trap. On impulse he stabs through the tapestry. The alternative would have been to be captured by the guards and thrown in a dungeon. His mother really thinks he is trying to murder her, and Polonius can't see what is going on.
With Rosencrantz and Guildenstern, they are on their way to England. Hamlet's life is in danger. He can't destroy the letter. He has to make sure the two men are silenced immediately or they will tell the English authorities that Hamlet is mad, killed Polonius, is homocidal, and will probably tell them that Claudius wants him beheaded. If the English just hold Hamlet and send a messenger to Claudius, he will confirm that he wants Hamlet executed. Hamlet would not have sent Rosencrantz and Guildenstern to be killed immediately unless he could see no other alternative.
Hamlet is courageous and resourceful. He always acts forcefully and decisively when he is acting on impulse and not thinking--as when he boards the pirate ship single-handedly, when he kills Laertes with the poisoned foil, and when he kills Claudius.