What news do voltimand and cornelius bring back from norway?

Fortinbras will not attack Denmark. 
Good news. The King of Norway has diverted his nephew Fortinbras to an attack on Poland instead of Norway (for now). There is word-play that makes this parallel Hamlet's killing of Polonius instead of Claudius.

If he breaks the law then he had to resign from his post and so he'll lose his/her powers.