The article used the expert method Thomas L. Saaty - Analitic Hierarch Process (AHP), in the domestic literature it is well-established name method of analysis of hierarchies (MAI). It has a software implementation of the Super Decisions developed under the guidance of the author. The possibility of considering the role of human factor in complex systems with the help of MAI can be used to analyze the problem/situation that can be represented as a system with complex hierarchical structure of the interaction between the elements. The method is based on a meaningful model. MAI allows to evaluate the effectiveness of possible solutions (alternatives) by introducing the integral index, which is determined by the results of the analysis of the four hierarchies: benefits, opportunities, costs and risks. The values of the integral index for each alternative is calculated based on the relative values of the alternatives in the four hierarchies. The best alternative is determined according to the optimality criterion. The article demonstrates the application of this approach to a specific situation to justify the selection of a method of settlement of international conflicts between the USA and Russia about avoiding the use of chemical weapons in Syria. The research results have confirmed the correctness of the choice of negotiations as the best alternative. This approach can be used as expert estimates to predict, and as a learning tool.