The terms of alliance are you do not enrich the guy we are protecting you from.
It is that simple!
It is that simple!
In the cold war, it was the USSR which was more dependent. Without food grown in North America, they were (IIRC) looking at WWII levels of rationing, in the 80s, which would have made people pretty unhappy. They sold oil to buy this food, but most of the west could have got by without this trade. (Not sure how dependent W.Germany was, at that point.)
Germany is more than able to protect itself against Russia.
Germany only have ~300 tanks.
It is not by any stretch of imagination.
France has 530 MBTs, Spain 550, and Italy 480. This compares favourably with the 2600 Russian tanks, and with proper logistical backbone, advanced air support, infantry support, and competent missile defence systems, is way more than necessary to stall a Russian offensive.
Of course, once the Russian offensive is stalled, Germany alone can vastly outproduce Russia, and that's the worst case scenario.
The US is not necessary for Germany to defend against Russia.