Here’s the problem with House Lannister in Game of Thrones season 7: it’s shrunk. When Tywin Lannister died in season 4, it was riding high. In addition to the armies of the Westerlands, the Lannisters commanded the City Watch of King’s Landing and had alliances with the Tyrells of the Reach and the Freys of the Riverlands. And on top of that, Tywin was doing his damnedest to bring Dorne into the fold on the Lannister side.
Fast forward two years later, and everything’s gone to hell. Tywin’s daughter Cersei empowered the Faith Militant in season 5 with the express purpose of undermining the Tyrells. The Faith turned on her soon enough, and while Cersei got rid of them by blowing up the Sept of Baelor in the season 6 finale, she also killed Mace, Loras, and Margaery Tyrell, effectively burning any bridges she had with Olenna Tyrell, the family’s last surviving member. Things in Dorne took a tumble, too, and now Ellaria Sand and her allies are hell-bent on toppling Cersei from the throne.
Even the Riverlands are in disarray. With Walder Frey dead, there’s no telling what will happen with them as his many descendants squabble for his old position. Cersei may be queen of the Seven Kingdoms, but she can really only depend on one to be loyal.
There are internal problems, too. Recall that Jaime Lannister, Cersei’s twin brother and lover, killed the Mad King Aerys Targaryen for threatening to blow up King’s Landing lest it fall into the hands of his enemy. Now, his sister has blown up a portion of it. I imagine he’s having some seriously uncomfortable flashbacks right about now.
So Cersei is beset by problems within and without. Can she possibly overcome them? Maybe. Depleted though her resources are, she still commands the armies of the Westerlands and the City Watch. And while she may have chased away her old allies, there could be others waiting in the wings. For example, in the second trailer, we saw Greyjoy ships pulling into Blackwater Bay. Might Cersei align herself with Euron Greyjoy and his freshly built fleet?
And if all else fails, she still has a gargantuan bodyguard in the Mountain and her own mad scientist — the mysterious Qyburn — to help her. The odds may look stacked against her right now, but as the Sparrows and the Tyrells learned too late, it doesn’t pay to underestimate Cersei Lannister.