Bargaining in the international arena is intrinsically positional. Negotiators are often instructed by their governments not to improvise or explore new options when they meet with their counterparts—even though the invention of additional tradeoffs or packages might well produce “better” results for all sides. This article describes an approach that we call “parallel informal negotiation” which encourages a collaborative effort between contending groups that were officially not even allowed to interact: international trade and environment poli