Gertrude's Motives

As Act 4, Scene 1 opens, Hamlet has just killed Polonius and gone to hide the body. Gertrude, distressed by what she has just witnessed, goes to Claudius. Claudius inquires about Hamlet, and this is what she replies:


"[He is] Mad as the sea and wind when both contend
Which is the mightier. In his lawless fit,
Behind the arras hearing something stir, 
Whips out his rapier, cries, "a rat, a rat!" 
And in this brainish apprehension kills
The unseen good old man."

In order to better understand Gertrude's character, we need to look closer at her choice of words. Firstly, although she has just been told by her son that he is only acting mad, Gertrude claims Hamlet is insane. She says he is like "the sea and wind when both contend which is the mightier." She sees his reason and his madness battling against each other, and is not sure which has won. Gertrude calls his action a "lawless fit" in "brainish apprehension". Both of these phrases seem to say that Hamlet's actions were beyond his control. But did Gertrude really think her son was mad? She had just come from talking with him, where he warns her to "lay not that flattering unction to [her]soul That not [her] trespass but [his] madness speaks." He tells her very explicitly that he is not truly mad, and that if she blames her guilt on this she is lying to herself. So did Getrude listen to her son? Did she believe she was at fault and had done a terrible thing in marrying Claudius? I think so.

It is very possible that in this excerpt Gertrude is portraying Hamlet to be more crazy than necessary to protect him from Claudius. Claudius must have realized from the play that Hamlet was on to him. If Hamlet was himself (ie. not crazy), he could be in immediate danger from Claudius. It is possible that Gertrude thinks the only way to keep her son safe from Claudius is to help give him the excuse of being insane. If so, she is mistaken, because Claudius does not intend on Hamlet leaving England alive. But Gertrude does try  to save her son whenever she can, here, and in the final scene when she drinks the poison meant for Hamlet. Did she know the cup was poisoned? Was drinking that cup one last attempt at keeping her son alive? Did Gertrude believe her son had gone mad? Or did she turn against her husband and proactively work to keep Hamlet safe? We'll never know for sure..