On the issue of sustainable management of social and economic systems in pursuit of the appropriate defensive capacity of the State
<b>Importance</b> Managing social and economic systems of the State and attaining the required defensive capacity constitute a relevant and significant issue, since emerging geopolitical conditions, the need to combat world terrorism and conflict resolution methods are of growing importance for the defensive capacity of the State. <br></br> <b>Objectives</b> We select and justify conditions for ensuring the required defensive capacity of the State through the management of social and economic systems. <br></br> <b>Methods</b> To achieve this goal and address the issues, we devise a model reflecting how social, economic and military systems of the State influence each other. To analyze the results, methods of the theory of economic oscillations were used, and the optimal solution was found using iterative numerical methods. <br></br> <b>Results</b> We outline a methodological approach, which allows to assess the benchmark adjustment to principle items of the budget so to reach the required defensive capacity in line with the existing social and economic systems of the State. <br></br> <b>Conclusions and Relevance</b> When managing the social and economic systems of the State and ensuring the required defensive capacity, it is advisable to use the proposed methodological approach, which allows not only to assess consequences of a certain management decision, but also to formulate recommendations for achieving the required result. The findings can be used to improve techniques and methods for managing and planning the development of social and economic systems of the State, as well as to justify the required, affordable costs for ensuring the defensive capacity of the State.