Mearsheimer argues that a great power must have sufficient conventional force to fight against a more powerful one, and a conflict will occur between two great powers- the US and China. However, he does not define "sufficient conventional force" specifically, nor list great powers strictly based on the above requirement in his empirical study. Among common indicators of national power, military expenditure performs better than military manpower or the Composite Indicator of National Capabilities for measuring Mearsheimer's concept of power. Since the US spends far more than China in arms, the latter is not qualified as a great power in Mearsheimer's sense unless the gap of expenditure between them decreases.