Germany started slow,
I think arguing over facts with you is pointless because you only see what you wnat to see and ignore all the rest. I'm only saying good luck with your miliatry help for Ukraine.
Do you think you can guarantee their safety and do it without Poland? Looks like you think that Poland is only a doormat that lies between Germany and Ukraine.
Don't come running here and shouting foul when you find different.
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Germany as a modern state came out as a necessity due to an internal power struggle within HRE and invasions by Sweden and France.
The Polish Crown indulgence to their Prussian province I would say!
The general rule of cooperation would be simple if there is a conflict of interest when it comes to a firm, they either left to a fair free market competition or the lines redrawn on both sides, tit for tat, with no interference in Poland developing its infrastructure, nor interference into internal Polish affairs and Poland can promise the same.
It is not that complicated after all. However, when money, greed, and prejudice are at play is not that easy to implement.