Its very naive and easy to think that Germans and Europeans did not rearm because they don't want to. Its because they can't. You cannot create a militaristic society with a huge military without stroking nationalism. Military might and pride in your own nation goes hand in hand. When that happens, what is stopping Germans to think that maybe they don't need to live under American boots. What is stopping a far right government from coming to power and stroke racist sentiments against Slavic polish people who took German land for example.
What is stopping Poland from becoming even more nationalistic and thinking of taking over their lost lands?
Remember the original purpose of Nato: To keep germans down and keep americans in. So, if Americans are getting out to focus on China, and Germans are no longer kept down and becomes militarily powerful, The likelihood of rise in nationalism and eventual break up of Nato will increase.
Anything that increases nationalism and far right tendency is good for Russia and good for China who wants to break the EU alliance into smaller pieces that are fighting each other.
