I don't know. I'm not an expert on foreign policy. But I would hope that it would be more than "nothing".
I can't remember offhand a precedent for something like this, where an apparently state sanctioned action from an "unfriendly" country came with an implied terrorist threat against Americans on US soil, and had a direct affect on businesses (Sony, and all the movie theaters that planned to carry the movie). One has to assume that there is a negative financial impact to a number of entities. That cannot be ignored.