The establishment and specialization of separate sectors was the authority's response to tackle with the threats posed to the state itself and citizens. The development of armies and law enforcement bodies was usually independent, addressing particular needs descended from external and internal threats. Nowadays, western countries' citizens experiencing long time of stability and peace on its own territory are likely to start questioning budgetary expenditures on army. Some of them raise that, the internal security should be the issue of major concern. At the very same time, the threats to the state and its citizens dynamically change forcing public administration to reconsider the structures responsible for preventing and counteracting them. Terrorism problem requires inter-agency approach and close cooperation between military and civil security sector. Crisis management system envisages common approach and joint reaction of almost all state and self-governed authorities. The change of domestic and international environment encourages reconsidering tasks and organization of modern armed forces and institutions responsible for safety and public order. According to author, it is worth considering further enhancement of double-use formations, common training, partially standardized procedures, mutual help, exchanging resources, legal provisions allowing the governments to use armed forces to take partial responsibility for maintaining public order in peace time. The final conclusion of the article encourages not only tightening the cooperation between Ministry of Interior and Ministry of Defense, but also among particular institutions and services subordinated to those Ministries. (Published Abstract)