I don't know that it really gives any insight into what the government is doing: that part of the movie is pure hokum. But I agree that it's a great movie, and I really enjoyed it.
I know that your post is from 6 months ago... but I wanted to say that I loved this movie as well. Have you seen Enemy of the State? Supposivly, this movie is similiar to Dejavu. I have it here at my house, but have not watched it yet.