INTRODUCTION In the last decade, the defence system of the Republic of Slovenia has faced challenges in financial, human and material resources, which, given the increasingly unpredictable and uncertain international security environment, hinders its development and operation in accordance with the law and the adopted development guidance and planning documents. The Defence White Paper of the Republic of Slovenia is a strategic document outlining the vision for long-term development, the functioning of Slovenia’s defence system, and the achievement of key defence objectives by 2035. The Paper explains the policy framework and commitments for adapting the defence system to changes in the security environment. It takes into account the measures to strengthen Slovenia’s defence capacity, which were proposed in the Strategic Defence Review 2016, and in NATO’s defence planning and capabilities assessments and other findings on the condition of the defence system. The Defence White Paper provides planning guidance based on realistic medium-term bases for pursuing the objectives of the defence system’s development in the long term. It recognizes the effects of the deterioration in the security environment, the emergence of new technological trends, and demographic trends in the Republic of Slovenia and abroad. It expresses the determination of the Republic of Slovenia to strengthen its defence system, and stresses the need for the implementation of measures in the field of defence. The greatest challenges for the development of the defence system, especially for the Slovenian Armed Forces as the entity responsible for military defence, are to reach the planned number of personnel, complete its professionalization, continue with modernization, and appropriately fund its operation and development. The purpose of the Defence White Paper is to define the gradual and long-term development of Slovenia’s defence system, in order to ensure the necessary level of capacity and preparedness for the implementation of national defence and the fulfilment of the adopted international obligations. It takes into account the comprehensive approach and importance of the resilience of the country and society as a whole to various forms of security threats and risks. The following points were taken into account when preparing the Defence White Paper: – The complexity, variability and uncertainty of the future international security environment; – The appropriate organization and effective defence of the Republic of Slovenia; – The national defence of the Republic of Slovenia as part of the collective defence within the framework of NATO and the common security and defence policy of the European Union; – The primary responsibility of the Republic of Slovenia to ensure the capacity, preparedness, resilience and sustainability of the national defence; – The unfavorable long-term demographic trends in the Republic of Slovenia and abroad; – The poor competitiveness of the military profession in the labour market; – The consequences of the lack of financial resources and investments in the development of defence capacity in the past. 6