Earlier quoted context omitted.
Don't forget to automate defence (yah that one, military), and how to prevent any interested party in controlling that automated defence system.
I think Americans over estimate how much investment in defense is needed. Massive defense spending is needed when you’re abusing the rest of the world. Less so if you’re not.
I don't think you understand the concept of risk, particularly as it pertains to things like war and armed conflict.
Defense spending always looks excessive and unnecessary until you need it. Saying a country overestimates how much defense spending they need is like saying you don't need car insurance because you've never been in an accident.
Wars are similar to car accidents. We're really bad at predicting when we're going to get into one and it can be a whole lot worse than we ever could have imagined.
Additionally for most western countries, the U.S. military acts as a fail-safe of sorts. If Belgium, for instance, underestimates their defense needs they know at some point the U.S. will jump in to help them if need be, which is largely what's happening in Ukraine right now.
By contrast, if the U.S. underestimates its defense needs and suddenly finds itself under attack, say by the Chinese, who exactly would come and save them?