In fact, US heightened military spending can create employment additional economic activity and contributes to the military weapon development of new technologies, which can bring advantages into other industries in US. For long term economic influence, US military weapon research and development on creating employment would potentially have the same low cost economic benefit in US. For example, US economy had higher GDP growth in the Afghanistan and Iraq war period. Another benefit is that US had appropriate conditions for future growth after the Second World War great depression period. It was a sharp decline in income inequality and the trend in declining inequality standard after the Second World War great depression period. Thus, America's human cost military spending could bring indirect military weapon research and development on creating employment benefit and it would potentially have the same low cost economic benefit in US. However, in the war period, the higher levels of government military weapon spending with war tends to generate some positive economic benefits in the short-term period, specifically through increases in economic growth during spending booms after war period. Why it can bring GDP growth in the US war period. In general, by the end of World Ward II, US GDP was over 120 % and tax revenue increased more than three times to over 20% of GDP. However, GDP growth there was are increase in the trend lines after the war had finished when unemployment was eliminated, recovery was well underway prior to the war, are the key counterfactual is whether similar spending on US public works would have generated even more growth. However, US macroeconomic history over the past seventy years, that there are a number of negative economic effects from conducting any wars. But, there have also positive benefits of increases US government spending on military industry. Moreover, when an economy has excess capacity and unemployment, it is possible that increasing military spending can provide an important stimulus. When military and defense spending is important in providing security for the US nation as well as helping to support and protect US's national affect. So, in war economic view point, it will bring this question: Is efficiency or justification for any particular macroeconomic effects of war spending for US?