Earlier quoted context omitted.
Its complacency, at least in Western Europe. Centuries of being the world's leading powers have left an underlying sense of being at the top is just normal and is a position that does not need work to maintain. Even those who might accept this is no longer true intellectually find it hard to internalise.
I don't think that's the current problem. It was up to, perhaps, the Suez crisis or up until decolonisation, but since then I think we've mostly internalised that America (and more recently China) have been the leading powers. The current complacency, one which we are currently still in the process of unwinding from (it will take years) is that of trade turning violent enemies into mutually beneficial growth opportun…
Spending on defence is expensive, but its a lot cheaper than an actual war - "if you want peace, prepare for war"