This article focuses on the role of threats in negotiations. Broadly speaking, a threat is a proposition that issues demands and warns of the costs of noncompliance. Even if neither party resorts to them, potential threats shadow most negotiations. Researchers have found that people actually evaluate their counterparts more favorably when they combine promises with threats rather than extend promises alone. Whereas promises encourage exploitation, the threat of punishment motivates cooperation. Professor Jeanne Brett of Northwestern University and her colleagues have identified three situations in which threats can be a necessary and effective tactic. First, as negotiators attempt to push past a heated deadlock, threats might be required to get the other party to come to the bargaining table. Threatening aggression is one way to get representatives of an obstinate country, for example, to attend peace talks. Second, threats can be a weapon against recalcitrance, steering a negotiation from impasse toward settlement. Finally, well-crafted threats may ensure that an agreement will survive the negotiation and secure implementation as well as follow-through.