Why does the USA spend so much money on her military, compared to other countries? $682Bn compared to $166Bn by China, the second biggest spender?

Why does the USA spend so much money on her military, compared to other countries? $682Bn compared to $166Bn by China, the second biggest spender?

Answer

There are a few big factors at play.

First, the US came out of WWII relatively intact. Unlike most of the rest of the developed industrial world, we did not have a major war fought right on top of us. Our industrial centers were not bombed into oblivion, so we were in a good post-war position to be the political, military and economic counter to the rising Soviet empire.

Second, the problem of communism - which, remember, was determined to "defeat" capitalism - required a military sufficiently strong to dissuade communist aggression. Not to defeat it directly, but to make it obviously futile or counter-productive, so that it would not expand into more and more theaters of potential conflict. However, the Cold War policy of containment would not work if it was just the US defending itself. It would be like trying to deal with an ant infestation with only enough pesticide for one room. So we needed a bigger military to not only extend the umbrella, but also to persuade potential allies to back our play.

That leads to the third factor. The US building a massive, global defense system allowed other countries to reduce their own defense budgets. This was good, to the extent that it limited regional volatility, but it also meant that a significant reduction in the US defense capacity could create a power vacuum that our allies were not entirely capable of filling. If the US substantially drew down the defense umbrella, a lot of countries would feel the need to ramp up their own defense spending. This makes it a lot more likely that previously-containable conflicts could blow up into all-out wars.

Think of it like your local police. Without a central police force, everybody would be directly responsible for their own protection. That would mean a lot of guns, a lot of paranoia and probably some warlords. The existence of a police force reduces the likelihood of that potentially volatile situation.

TL;DR: If the US didn't have a massive military, other countries would have to build up their own militaries, making regional conflicts and even world wars more likely.