Warning: this post contains spoilers for the season finale of Game of Thrones.

The most surprising moment of last night's satisfying-but-uneven season finale of Game of Thrones came when Sansa Stark finally stood up to Petyr "Littlefinger" Baelish, the quintessential man behind the curtain whose various machinations cost the Starks everything. Finally caught in his own web of lies, Littlefinger begs for his life before Arya Stark puts an end to him, once and for all.

But before Littlefinger dies, Sansa thanks him for "all the many lessons" in deception, self-preservation, and statecraft he taught her over the years. Indeed, Littlefinger gave Sansa a momentous gift: the ability, and likely the opportunity, to become Queen of the Andals and the First Men, Ruler of the Seven Kingdoms, and Protector of the Realm. (More on how she'll get there in a minute.)

The least surprising moment of "The Dragon and the Wolf" came immediately after Littlefinger's death, in the very next scene. Back in King's Landing, Jamie Lannister learns that his sister, Queen Cersei, has no intention of honoring the pact she made with Jon Snow, the king of the North, and Daenerys Targaryen, a rival claimant for the Iron Throne, to band together to fight the army of the dead. Her reasons for doing so are entirely rational: her armies probably wouldn't make the difference in the battle with the White Walkers, and even if the living triumph, the other members of the pact fully intend to continue warring with Cersei once the threat of zombie-nuclear winter is over. It makes more sense for the queen to strengthen her position and prepare to confront whichever enemy survives the battle in the north. Cersei has no interest in planning for a future in which she is not the ruler of Westeros—if she is going to lose the conflict, then it doesn't matter to her who wins, or even survives at all.

Indeed, if her rivals behaved similarly selfishly they might have actually overcome this inherent collective action problem. Daenerys could have threatened to feed Cersei to her dragon unless she got what she wanted from the elder queen, and she could have taken Jamie—the only other person Cersei cares about, as evidence by Cersei's unwillingness to hurt him—as a hostage to ensure compliance. Instead, noble-hearted Daenerys and Jon are sailing north to their likely doom, while Cersei plots to reconquer the kingdoms. (At least they're enjoying a romantic boat trip.)

Which is why I expect the union of Ice and Fire is ultimately ill-fated, even though Jon and Daenerys are now together at last and seemingly in love. Of course, the audience knows something they do not: Jon is not a bastard son of Ned Stark. He is actually the son of Daenerys's dead brother, Prince Rhaegar, which means that his claim to the Iron Throne is stronger than hers. (Jon is the son of the last Targaryen king's son and heir, whereas Daeny is that king's daughter.) It's a relatively trivial level of incest, as far as Game of Thrones goes—Daenerys' parents, and Jon's grandparents, were siblings, and Cersei has taken both her brother and cousin to bed—but it does introduce the possibility of conflict between Daeny and Jon. And even if they do overcome this conflict, defeat the White Walkers, beat Cersei Lannister, get married, and jointly occupy the Iron Throne, they still have a problem: Daeny is infertile. Unless the show undoes this plot point (which would be a fairly obnoxious cheat), a Daeny-Jon partnership could never produce an heir.

Which brings us back to the Sansa prediction. If Jon and Daeny die fighting the White Walkers, and Cersei is dispatched by some other means—possibly by Jamie, for the good of the realm—then Sansa will be left as the obvious choice to rule the kingdoms. She already possesses the best qualities of these other figures: like Daeny, she inspires devotion among her followers, like Jon, she cares about the good of the realm, and like Cersei, she promotes her family's interests. She is a loyal person, but her loyalty is tempered by practicality. And she has her other siblings—the all-seeing Bran and awesomely powerful Arya—to help advise and carry out her plans.

Last night's revelation regarding Jon's true parentage also provides a path for Sansa to legitimately claim the throne. If Jon and Daeny were to die, either in the battle with the White Walkers, in the conflict with Cersei, or childless, much later in life, then their next-of-kin would be Jon's eldest cousin: Sansa.

Such an ending would be narratively satisfying—relative good triumphing over relative evil, and all that—while still upholding the political realism of Game of Thrones. It's not enough to be more moral than your enemies, you have to be better and smarter, too. Dispatching Littlefinger is the best evidence yet that Sansa is the figure who embodies this creed.