He then dominates the conversation to talk shit about Radagast for a while. Trust me, I totally understand.
As Saruman continues to insult Radagast, Galadriel telepathically communicates to Gandalf, asking him to show the rest of them what he's hiding. Gandalf does so, interrupting Saruman by revealing the Morgul Blade. Galadriel recognizes it as a relic of Mordor, as Elrond hesitantly pulls aside the fabric covering it. Galadriel is frightened at the implications; this sword belonged to the Witch King of Angmar, and was buried with him in his tomb at Rhudaur. Elrond does not see how this is possible; powerful spells had been placed over that tomb. Saruman asks if there is any proof that this weapon came from Angmar's grave, to which Gandalf admits there is none. Saruman reviews the facts, and finds them to be meager proof of Sauron's return. He furthermore cannot condone Thorin's quest. Galadriel speaks to Gandalf telepathically again, warning him that the dwarves are leaving. He already knew, however, and coyly says nothing of it to the rest.
The Book: No such scene occurs. The meeting of the White Council is mentioned in the appendices of Return of the King, but it is never discussed or even alluded to in The Hobbit. The White Council does meet around this time, but to plan an attack on Dol Guldur; they had known Sauron was present at the old fortress for years by the time Bilbo Baggins joins the Company. Sauron had been defeated almost three thousand years ago, not four hundred. The Witch King of Angmar never died, and therefore did not have a tomb. The dwarves did not sneak away, and in fact, left Rivendell at the same time Gandalf did.
What difference does it make? Almost none, although the number of changes and mistakes here are actually pretty staggering. Very similar to the Battle of Azanulbizar, Peter Jackson has to condense a lot of history from the appendices into just a few scenes, and he does a rather remarkable job of conveying the most important information to an audience. Scenes like this flesh out the story of The Hobbit by giving Gandalf's mysterious disappearances some narrative focus, and help to tie together the plots of The Hobbit and Lord of the Rings. What matters is that the White Council meets, discusses the growing threat of the Necromancer, realize he is Sauron, and attack his stronghold at Dol Guldur. In a narrative sense, it is not strictly important to show these meetings happening over the course of centuries.
My Opinion: Hoo boy. I got opinions about this.
I like that Peter Jackson decided to include Gandalf's activities with the White Council in his portrayal of The Hobbit, but I take issue with some of the ways he goes about it. The Witch King of Angmar, for example, never died. He never had a tomb, and finding his sword would not be evidence of any evil magic surging back. This is the opposite of what Peter Jackson did with Azog - instead of pretending a dead character was still alive, he makes a living character dead. This goes against Tolkein's versions of events, and I cannot see the benefit to such a change. Is it so that the title "Necromancer" makes more sense? Is it solely to set up the scene in Desolation of Smaug where Gandalf investigates the tomb? Just remember, every time a change is made to "improve" the source novels, the movies become just a little less faithful.
Elrond makes a comment about how they had been at peace for "four hundred years." He calls it a hard-earned "Watchful Peace." I am not sure what Peter Jackson is trying to communicate with this line. Sauron's defeat at the end of the Third Age was almost three thousand years before the Quest for Erebor. If this is a reference to the amount of time since the defeat of the enemy, they are way off. However, there actually is a four hundred year period referred to as the Watchful Peace - the first time Gandalf investigates Dol Guldur, Sauron retreats and hides in the east until four centuries later. That's the Watchful Peace. The Watchful Peace ends, the White Council realizes that Sauron and the Necromancer are the same entity, and, years later, the events of The Hobbit start. It doesn't matter if Peter Jackson's "Watchful Peace" refers to the peace since Sauron was defeated, or the segment of Tolkein's history actually called the Watchful Peace. Either way you slice it, he messed this one up.
You may have pulled like six things out of various appendices and expertly woven them into the narrative with a few sentences, but you got some of the dates wrong Peter Jackson! Do you even care about the books?
I appreciate the way Peter Jackson decided to play up the threats of trolls and orcs as a precursor to Sauron's return. The book did not make any special deal of the trolls presence or the evil spiders, and of course, the orc pack led by Azog wasn't in the book at all. Attributing these things to some dark lord regaining power ties everything into a neat little package that gives the story a little more narrative cohesion. Using Radagast as a catalyst was a good choice; it stands to reason that, given his proximity to Dol Guldur, and an Istari to boot, he would have been one of the first to notice Sauron's presence in Mirkwood.
Saruman, by the way, was still a bit of a contrarian in the book, but for a different reason. He at first refuses to allow an attack on Dol Guldur, but that's because he desires the One Ring for himself. He only agrees after he realizes that an attack on Sauron would be necessary for him to get the One Ring before Sauron does. He doesn't become an agent of Sauron's until about a year before Bilbo Baggins' farewell feast in the Shire. I have no idea what is up with his attitude here in the movie. Is he just being his usual self: logical, efficient, and a bit of an ass? Is he trying to get the Ring for himself? Is he already under the thrall of Sauron? The timeline has been messed with so badly it's hard to say what exactly Peter Jackson is doing with the character.
Either way, his argument that "Sauron can never again regain his full strength" is... an odd choice. The wizards were sent to Middle Earth two thousand years ago for one purpose: to keep an eye on Sauron, who is a risk of returning to full strength once he gets the Ring. This is the purpose of the Istari. I mean, literally, its the reason there are wizards at all. What the hell was Gandalf doing for the past millennium that he's just now getting around to looking into things? Why is Saruman rejecting the idea, and dismissing Sauron as a threat entirely? I get that this may be a consequence of compressing all the White Council meetings into one, but it really makes Gandalf and Saruman look bad at their jobs.
"I'm the only wizard without a drug habit or a dumb hat, what more do you want from me?"