John Proctor's last speech in Act III is important because it points out that he knows what the court in Salem is doing is wrong and that they will all be punished for allowing innocent people to die. It is also showing that he not only thinks the members of the court are to blame but that he is as well because he did not come forward when it all started and tell the court that Abigail was lying because he didn't want people to know he was a "lecher".
