About four years from the commencement of military expansion in '35. Though they weren't really finished building it by the time the balloon went up. They just had the good fortune that neither were the French (and the British were just pitiful).

But that's not the question you need to ask yourself. The question you need to ask yourself is when the political dynamic had moved to where war could no longer be avoided. And that wasn't '39. It was certainly some time after '29, most probably even after the '33 Nazi takeover. Perhaps even sometime after the beginning of the '35 military buildup. But probably not after the '38 Anshluss, and almost certainly not after the first München conference.

So I'm thinking that once visible military buildup commences, you have probably passed the mark for 50 % probability of war.

I'll leave it to someone more knowledgeable about the particulars to discuss the lead-up to the wars in Spain and China.

- Jake

If you only spend 20 minutes of the rest of your life on economics, go spend them here.