Mono-white prison in modern. Ive been working on this deck for a while. Ive never had the balls to run it in a main event at an open or GP, but I have played many side events and in-store weekly tournaments. I have had some very good results with the deck in those events, but the most notable achievement was beating Reid Duke with it in a challenge match at GP D.C. last year. The most recent addition to the deck are 3x pithing needles to the mainboard which I added after Jim Davis blew me out with a turn 3 Karn.
The decks worst matchups are by far Infect and Tron. The needles are really the only maindeck answer to Karn/Ugin, and a turn 4 Ulamog is extremely hard to come back from. Infect is just extremely fast and wall of omens only stops 1 of their 3 main threats. Runed halo is our best mainboard card in this matchup, and you can hopefully curve into bridge/bottle before they get lethal.
The Lock:
When you have both copies of Privileged Position in play, or one copy along with a copy of Greater Auramancy they protect each other along with ALL of your other permanents. Leyline of Sanctity protects you, Gideon makes his emblem with gives you a Platinum Angel.
The only way to break the lock are non-targeting wipes like engineered explosives, back to nature, creeping corrosion, fracturing gust, ratchet bomb, or Ugin. The only ones you will run into pre-board are explosives and Ugin, and pithing needle stops them. Post-board you may see some back to nature if bogles are popular at the time, while gust/corrosion are a little less likely but still potential threats. We have a full playset of nevermore to bring in to give us even more protection from cards that can break our lock.
Winning the game:
We have 3 ways to win. We can win with approach, mill them out with sands of delirium (this can also mill us back down to our approach), or with the lock in place we can actually deck our opponent. We can draw our entire deck 1 card at a time and not lose due to the gideon emblem. Eventually our opponent will deck out.