This study developed a new defensive model for global voice communications. It uses a n-person, zero-sum, cooperative and non-cooperative game to optimize the coalitions revenue after the possibility of a network service provider being tampered by an adversary. This research optimized two measures of effectiveness (coalition revenue and network provider revenue) of international telecommunications coalitions by hardening network service providers and improving their respective revenue with incentives. A multi-criteria optimization problem was developed to establish the strategic competition between the coalition defender and attacker. Irrespective of the amount of incentives, a applicable hardening and tampering strategy can be obtained. All methods and models are general and could be easily adapted to other specific applications. Examples of analysis was conducted on a sample network of seven nodes and presented in this study. It was shown that the option to harden NSPs has measurable value whether or not an incentive is provided for the coalition. In addition, the adversary's tampering strategy is revealed in the shadow prices associated with the game constraints. Analysis proved that two objective functions have different measures of effectiveness. A network optimized for one objective is more than likely not optimized for the other objective.