Is the SIPRI estimate of military expenditure a reliable indicator of the power of states?

The analysis of military expenditure has always been a matter of debate, as to its content, its significance for national defence, the value of international and intertemporal comparisons, the quality of the figures provided and their suitability for econometric studies. SIPRI has undertaken new work to refine its conception of military expenditure, not taking over the work done by the United Nations for the construction of an information matrix on the national defence effort. In fact, precise knowledge of military expenditure is probably only of real interest for analysing its influence on economic variables. Military expenditure is first and foremost a cost for the public sector, which provides a security service whose effectiveness is difficult to measure in view of the sums involved. The content of armaments (nuclear or cyber warfare) is not really indicative of the quality of a country's defence. Thus, despite the crisis suffered by the Soviet military-industrial complex, Russia remains a great military power because of the threat of its nuclear missiles, which make it little subject to external attack. Similarly, despite the fact that its nuclear weapons are virtually useless in local theaters of conflict, the United States' military engagements in Afghanistan and Iraq have been failures.