When was the last time a relatively poor country successfully attacked and conquered a richer country? You history buffs might come up with some examples, but I think they would be strange exceptions.
I think someone smart could develop a theory that a strong economy is as good a national defense as having excellent weapons. Obviously you need a minimum baseline military deterrent. But anything beyond that might be a waste. Your international trading partners would band together to help you out if you are attacked, to protect their own economic interests.
I don’t know how many nukes the United States has pointed toward China, but one would be too many. China isn’t going to attack its biggest customer. And in the unlikely event that some other country attacks China, we’d offer military assistance in a heartbeat. There’s too much money at stake on both sides.
I wonder if you could make all war decisions on a purely economic basis and come out with the answer that protects the most lives as a side effect. For example, the United States had an economic interest in the smaller war in Afghanistan, to prevent more attacks on the homeland. But the war in Iraq was characterized from the start as “you break it, you bought it.” That’s bad economics.
This is another reason I can’t be president. Whenever a military question came up, my first question would be whether it is a positive return on investment. That would be the opposite of good leadership, but it might keep the country safer and richer.