Bargaining power comes from the quality of your best alternative to agreement, not from your need or your rhetoric.
Fisher and Ury's central point in Getting to Yes, 1981: improve your alternative before you improve your arguments. A party with no alternative is negotiating terms, not price.
In practice
- A supplier holds firm not because their pitch is good but because they have three other buyers; the negotiation was decided before either side spoke.
- A tenant who has found somewhere else to live negotiates a rent increase very differently from one who has not looked.