i disagree, well actually first i'll agree, I hate portman. She annoys me. I almost didn't see it because of her. Now to the disagreement. The plot was very easy to figure out, there were no twists and you were not surprised by the events unfolding in the manner in which they did. In my opinion the movie didn't rely on plot twists. The movie was built on the audience being "in on the secret" of what was going to happen. The only ones surprised by the plot were the characters. I believe it was more about the sheer inevitability and scale of the plans coming to fruition.
While portman's acting seemed flat the other actors in the film performed well. I didn't like that they took a couple political pop shots at the present administration, however I understand the political nature of the movie presents a proper opportunity for them. And in that framework it makes perfect sense.
If you haven't seen this film, I would recommend it highly.