Board Thread:TV Show Discussion/@comment-3035448-20170119043310/@comment-5014364-20170121211402

Literally poisoning him to death.

In the books, Littlefinger's plan is to marry Sansa to Sweetrobin Arryn's closet living male heir, his cousin Harold Hardyng (currently the Ward of Anya Waynwood). Harold is everything that Sweetrobin is not, a dashing young warrior, not unlike Robb Stark.

Littlefinger explains to Sansa in her last chapter in the current novels that his plan is to betroth Sansa to Harold, then reveal that she is Sansa Stark, and beseech the Vale lords to attack the Boltons to restore her position (which many of them want to do, particularly the Royces, it was only Lysa who prevented them from joining he war on Robb Stark's side).

But in order for Harold to be the new leader of the Vale....Sweetrobin has to go. A sickly young boy, mentally and emotionally stunted.

Sweetrobin even has epileptic seizures in the novels, for which his maester is medicating him with "sweetsleep" (the TV show calls it Essence of Nightshade for some reason when Cersei talks about it). In small doses it helps with shakes and seizures, larger doses can be fatal, and it builds up over time in your body.

Littlefinger is subtly having Sweetrobin's maester give him too much seizure medication, high doses which will build up over time and eventually kill him.

Littlefinger has told Sansa that the Harold Hardyng plan is dependent on Sweetrobin dying soon. She seems okay with this. Leading to debate of whether she's you know, acting for the greater good; Sweetrobin's lack of rulership will end up getting all the Vale lords killed, they need a strong leader now and they'll be destroyed if he stays as lord of he Vale.

No. Don't read anything into "no one can protect anyone". Stop reading into it. Sansa has ceased to be a coherent character who does things for in-universe reasons. It's not simply that we "disagree" with the TV writers' characterization, it's that they have no characterization. Why is Sansa not telling Jon about the Vale army? Officially "there was no reason, it was just to build dramatic tension".