Well, 1T/yr is not needed to defend against China.

Even ignoring nukes for a second, because its always possible for some future tech or situation to nullify them anyhow...... (not talking tomorrow, just in general)

China has a lot of people. China can make a huge army. However, China has thousands of miles of ocean between us and them. The idea that they could invade us is a nonstarter.

Nor would they want to.

If they were to pick a fight of that nature with the Anglos it would be with Australia, because they have lots of arable land with relatively few people, and its a lot closer.

Anyhow, the point is you can maintain a huge defence - and focus on important and relevant systems like navies and fighter planes and missiles and such - you dont need to maintain 10 Divisions of Heavy Armour ready to be used as an occupying force for whichever country we decide to topple tomorrow.

For who could be free when every other man's humour might domineer over him? - John Locke (2nd Treatise, sect 57)