Having sufficient capacity for violence is indispensable for the existence of a state. You need a military so you can kill people in other countries, and you need police so you can maintain an internal monopoly on violence. You can't have state-funded preschool if you don't have a state. The Ukrainians unfortunately are learning this the hard way right now.
You mean: America lives under the UK and France's shield. The last time that US soldiers died to defend France or the UK is a long time ago, much more recently French and UK soldiers died for (amongst others) the USA. Not that anybody seems to remember.
Oh and on a per-capita basis more people from the UK died in the Gulf war than from the USA.
But this isn't a matter of keeping score it is standing together and at least trying to maintain some kind of world order. One problem with that is that you may have to refrain from threatening your allies with invasion.
With 2% of GDP USA would take care of all its defense needs. USA does not need 11 aircraft carrier groups, about 100 nuclear-powered submarines, about 2,000 jet fighters, only God knows how many destroyers, to protect itself.
Effectively, no one. The CCP doesn’t have the logistics capability or manpower to manage the largest occupation in the history of the world from half a world away.
They can and do want to destabilize American hegemony, but that doesn’t necessitate an end to the American state. My read is they prefer something like the British model for ex-imperials.
