The aim of the article is to identify possible “follower” behaviour; it means to reveal countries following the average military burden of North Atlantic Treaty Organization (NATO) member states. To analyse the relationship between military expenditure of NATO member states and selected socio-economic variables (average military burden of NATO member states, gross domestic product, government expenditure (non-military), share of trade balance of gross domestic product and population), the Autoregressive Distributed Lag model has been used. The short-term results demonstrate follower behaviour, especially in the new NATO member states (effort to fulfil the commitment to spend 2% of gross domestic product on defence). The long-term results have revealed a positive relationship between military expenditures and the variable describing the average military burden of NATO member states in the traditional and also new NATO member states. A positive relationship between military expenditure and gross domestic product has also been observed in the majority of evaluated countries in the long-term model. The public good effect has been determined in six member states only, and the crowding out effect in five member states. A positive effect of the balance of trade on military expenditure has been observed in two countries only.

The present paper presents an alternative approach to determining rational defence spending of the Czech Republic concerning the evolution of a society’s wealth, expressed in terms of the financial valuation of tangible fixed assets. The authors describe the view that the government’s stated commitment to defence spending of 2% is a political decision that does not reflect the impact of the wealth achieved by society, the likelihood of an attack by a foreign power, and the expected level of damage caused by an attack. The authors present a model for determining rational defence spending based on the fair insurance model. The authors conclude that the rational expenditure on the defence of the Czech Republic’s wealth should be between 3.5% and 4.2% of GDP.

The article proposes a risk-based model for rational defence expenditure in NATO’s Bucharest Nine (B9) countries that integrates socioeconomic variables and challenges the 2 %-of-GDP benchmark. It contends that optimal funding should reflect both national wealth and the probability and expected consequences of a foreign attack. Applying a quantitative model spanning 2001–2024, with emphasis on the post-2014 environment after Russia’s seizure of Crimea, the authors correlate actual spending with perceived risk and analyse shifts in budgets, threat perceptions, and prosperity, revealing major gaps between observed and rationalised outlays. The results underscore the value of context-sensitive, evidence-grounded budgeting for strategic foresight, credible deterrence, and prudent resource allocation under uncertainty.