Perhaps the most common question I receive from the MBA students in my Decision Making & Negotiation Skill class is – what do I do when the other side is completely unreasonable or evil?

Robert Mnookin (Harvard) explores this question in his book Bargaining with the Devil: When to Negotiate and when to Fight. 

I won't attempt to summarize the entire book, but I share a few representative quotes below. (Page numbers correspond to the 2010 hardback edition).

"By 'Devil' I mean an enemy who has intentionally harmed you in the past or appears willing to harm you in the future. Someone you don't trust. An adversary whose behavior you may even see as evil." (pg. 1)

"An act is evil when it involves the intentional infliction of grievous harm on another human being in the circumstances where there is no adequate justification." (pg. 15)

Consider "Interests [of both sides]…Alternatives [of both sides]…Potential negotiated outcomes…Costs…Implementation…What issues of recognition and legitimacy are implicated in my decision" (pgs. 27-34).

"I believe there is reason to be deeply concerned whenever an agent or representative allows personal morality to override a rational analysis favoring negotiation – even with a devil." (pg. 49)

"If you bargain with the Devil, develop alternatives. You will need them if the deal doesn't work out." (pg. 81)

Using "empathy and assertiveness….A good negotiator has to do a lot of both." (pg. 134)

Remember to "listen first, talk second." (pg. 177)

"A common occupational hazard for mediators is getting hooked into taking responsibility for finding a solution….[The mediator's] responsibility is to help the parties better understand each other and their predicament, and then fashion their own solution." (pg. 237)

"'Should you bargain with the Devil?' If I were pressed to provide a one-sentence answer to this question, it would be: 'Not always, but more often than you feel like it.'" (pg. 261)

This is a difficult topic and doesn't fit neatly into bullet pointed format, but Robert Mnookin uses case studies throughout the book to explain his methods. The case studies come from political, business, and family disputes. The wise solutions are fact-dependant, but after reading the case studies you get a better sense of how to deal with difficult negotiations.