It's sustainable if your economy is... does math... 87.5 times the size of your opponent's. That's before accounting for any kind of marginal utility, which mig

It's sustainable if your economy is... does math... 87.5 times the size of your opponent's. That's before accounting for any kind of marginal utility, which might make it less painful for a very rich state or society to spend $70,000 than for a very poor one to spend $800. [EDIT] oh, without even going far-afield with second order effects, you'd also need to factor in the expected economic harm of each $800 rocket (on average) and the economic harm of the threat of $800 rockets landing more often (to, say, the tourism industry)