Time you boned up on your history. In WW2, Stalin and Hitler signed a pact to work together. They subsequently fell out. It was only later in the war that Hitler decided he had the might to take on Russia as well. And we all know what happened then!
Oldmac / arbel I agree with much of what you write but on this you are wrong. The pact was a marriage of convience that suited both well at the time. Part of the pact at the time was that Stalin got his fair share of Poland, agreed before signing. They still hated each other and knew it. Hitler was trying to show the world he did not want war by this pact although the history shows at the time he was allowed to annexe the Sudetenlands he was wanting war with the Russians but his generals insisted they still did not have the military power to defeat Russia so the pact also bought time and hopefully would deceive Stalin. They did not later fall out as they had never fallen in!
I do not think the Germans will seek any military build up, rather I believe they will be willing to do anything to save the European dream, even sacrifice a good chunk of their industrial base. History of 60 years ago is still to raw in Germany to allow militarism yet.
I have said before what we are seeing is the end of the WWII settlement as envisaged by France, Germany and Britain in post war Europe. That it survived so long is testament to their foresight. History has settled periods and unsettled periods and we are no different in that regard to our forefathers, we are not more educated, we are not more aggressive or pacifist we are just in a different situation though the course of human nature remains the same. We have just had a long settled period. True we have more gadgets and are more inter connected than ever before but how and if this will influence our actions when and if push comes to shove I doubt. The threads we see swirling about in the USA and Western Europe are the same as have been seen before though they never weave the same cloth twice.
What I find troubling is that there seems to be no outriders of some new vision to replace the rapidly declining current one. It looks like there's going to be a vacuum to fill and chaos will step in if nobody else does. There is an old soldiers saying, "the first thing to go in the battle is the first plan", so I don't think the first signs of a Brexit plan will necessarily give us much of a clue as to the look of the final settlement.
Change is only unsettling when you are not in charge of it, this is illustrated by the findings that single seat fighter pilots in WWII suffered less anxiety than bomber pilots, yet statistically they were more likely to die but they felt in control of their environment whereas bomber pilots felt they very little control of theirs. This insight should help us to think not so much about what the Brexit might do to our lives or businesses but more what can I do to improve my business right now. That's a Brexit plan that you can start on now.