Sometimes an opponent’s unreasonable behavior will be rooted in a desire to please a client or colleague. You may be able to move forward by “building a golden bridge”; i.e., framing their retreat from a hardline position as movement to a better solution. You might ask for your counterpart’s ideas and add to them rather then trying to promote your own.*
* My thanks to William Ury in the Harvard Program on Negotiation for the thoughts shared in this Tip.