Why did Sansa play her cards so close to her hand-embossed vest? I know why, and I teach my business clients this vital lesson every day. She did exactly the right thing for herself, and for the North.
Sansa was faced with Jon, who she has strong personal bonds with. He has a lot to offer:
- Combat and military strategy skills she needs;
- Substantial military resources and a strong reputation to help raise more troops;
- Objectives which align very closely with her own, especially in the short term.
She wisely enters into a partnership with him. However, Sansa recognizes that, like all partnerships, this one is imperfect:
- They were far from friends as children;
- Jon has advisers Sansa doesn't know or trust;
- Jon, while awesome, has substantial limitations as a politician and diplomat.
Sansa chooses to balance these factors by looking out for her own interests, while recognizing that strengthening her partnership is good for everyone. She doesn't tell Jon about her extra forces, and makes sure that she is seen leading the victorious party. She's just improved her military reputation and avoids the pitfalls of one of Jon or one of his advisers making a mess of things by engaging in a protracted siege of Winterfell or otherwise damaging the built-in advantage she had by having a large, secret force she could deploy at will.
A substantial part of my practice is partnership dissolution. When people, business plans, or the business environment change, once fruitful partnerships fall apart and leave valuable assets in their wake. Sometimes nasty litigation crops up around these dissolutions, sometimes it doesn't. In Westeros, it's swords instead of lawsuits, but the basic principle is the same. Sansa doesn't know if Jon is capable, how long he'll survive, or if she can trust him not to usurp her throne.
Sansa's moves are calculated, and would not have placed Jon in much danger if he'd stuck to the plan he had disclosed to her (involving a defensive position and trenches) instead of a doomed charge. She's working to maintain her partnership while being careful to maintain her own interests.
The legal lesson in this is that since partnerships can end, it is critical that each partner consider that possibility while forming and maintaining them. No matter how strong the bonds or how perfectly matched the motivations, a smart partner is careful to maximize their interest, maintain an element of control, and generate a personal brand that can persist beyond the partnership. That's exactly what Sansa did. It doesn't mean she doesn't care about Jon or doesn't want Jon to succeed, it just means she's smart enough to know that stuff happens and it's better to be ready for it than blind and unprepared.