Throughout the course of The Crucible, does Danforth change?

At the risk of giving him too much credit, I do think Danforth changes.  When the audience first meets him in Act Three, he seems to honestly believe that the girls are telling the truth when they accuse others of witchcraft.  That the Puritan religion admitted both the existence of witches as well as the possibility of the devil working constantly in their daily lives to tempt and corrupt them meant that Danforth could legitimately...

At the risk of giving him too much credit, I do think Danforth changes.  When the audience first meets him in Act Three, he seems to honestly believe that the girls are telling the truth when they accuse others of witchcraft.  That the Puritan religion admitted both the existence of witches as well as the possibility of the devil working constantly in their daily lives to tempt and corrupt them meant that Danforth could legitimately believe the seemingly wild stories the girls were telling him.  He says, "We burn a hot fire [in this court]; it melts down all concealment," and I think he believes that this is true because of the evidence (convincing to him and others) he's heard from both the girls and the people who confessed to witchcraft.

By Act 4, however, Danforth has changed.  I think he now recognizes that the girls were lying.  He calls Reverend Parris "a brainless man" now that Abigail and Mercy Lewis have robbed him and run off, and certainly Abigail's theft and flight make her look immoral and guilty.  Further, he seems more concerned about his and the court's authority now than he does about truth.  When Parris and Hale ask him to postpone the hangings, he refuses, saying, "Postponement now speaks a floundering on my part; reprieve or pardon must cast doubt upon the guilt of them that died till now."  Even if all those who've been hanged were innocent, he cannot now seem to admit the possibility because it would mean that he and the other judges have been tricked.  He swears that, if the town should rebel, he would rather hang them all than appear weak.  Therefore, during the course of the play, Danforth seems to have lost sight of what is important: truth.  By the end, retaining his own reputation, authority, and appearance of righteousness trumps his concern for truth.