Royal
Connoisseur of Exotic Pictures
I think her leverage to sacrifice Shireen will come from Roose's being content to sit behind his walls and let winter do his dirty work. He's right in that a siege is an autowin for him. Mel will try to pressure Stannis into burning Shireen to off Roose while he sits in Winterfell, either by making him strong enough again for him to fuck another shadow baby out of her or some other sort of killing ritual.2. He lights their encampment on fire. Melisandre finds some way to leverage to burn Shireen.