What a wonderful, sprawling, canon-compliant epic of a fic! I love stories about Ministry politics, and you've done a fine job of showing exactly how the Ministry might have responded to the existence of a group like the Order. I'm impressed by all the world-building you've down, how full and real all the characters are. Plus, so many great background historical details, like the "Squib Marches" of 1967. Everything fits into canon so well, but is more dense and interesting; I felt as if I were reading a real history.
And what a poignant, bittersweet, believable relationship you've given Alastor and Rufus (and poor Robards).