In my mind the quickest and simplest way to reduce military spending in the US is to cease the policy of playing policeman to the world. The military budget of NZ is, like every other ally, subsidized by the US (aka the US taxpayers). If that policy were to end I have a strong hunch NZ would need to meet or exceed 4.7% of GDP to secure itself. If charity begins at home its time for the US to be a little more charitable.