Is it possible to cancel Siege of Winterfell with He Calls It Thinking on the basis that it is a response?

I know you cannot cancel the effect of an agenda but this is a response… so? Can I?

Yes -- but you are not cancelling the Agenda, only the Response (and only that one time).

How exactly are you not "cancelling the Agenda"? I don't think you can cancel Siege by any means.

kauai1964 said:

The Response on Siege is an Agenda effect. You cannot cancel Agenda effects, no matter what type of effect they are. "Cannot" is absolute, so when the FAQ says "Further, the effects of an Agenda card cannot be canceled," it doesn't mean "except by He Calls It Thinking, or any other effect, that refers to the effects of the Agenda without using the word 'Agenda'." "Cannot" trumps everything.

The only thing that can stop Siege at Winterfell, other than not letting the guy win a military challenge, is Brienne of Tarth because she doesn't cancel anything - she prevents it from ever being triggered in the first place.

FAQ:

(4.12) Agendas

Agendas are not considered to be in play. Further, the effects of an Agenda card cannot be canceled.

I learned something new today :-)