WWI started in countries (Balkans) with the least economic interdependence, then pulled in more Western European countries through defense alliances. While technically someone could have put the brakes on, it was an autopilot sort of thing. The lesson of WWI is that if you're going to enter into defense agreements that obligate you, be careful to whom you're wedding yourself. In particular, don't wed yourself to someone who has much less to lose than you do.
One of the lessons from the prelude to WWII is to be careful about trade imbalances, as they can breed instability and radicalism. During the 1920s the US enjoyed huge trade surpluses with Europe, which caused all manner of monetary and labor dislocation in Europe. Worse, the US wasn't content with this surplus, so similar to modern China they erected additional barriers to imports to try to have their cake and eat it, too. These effects were amplified by the gold standard, which accelerated deflation and unemployment in Europe, and accelerated (stock market) inflation in the US. And of course all these ill effects were amplified again for Germany.
Toward the end of the 1920s and during the 1930s, the whole system was disassembled as every country, understandably, retreated to lick its wounds. Economic interdependence is critical to maintaining global security, but that interdependence itself isn't self-sustaining. It can fall apart if dislocations aren't managed well across the system. For example, the lessons from the 1990s and early 2000s is, "just go back to college or trade school" is an absolutely horrible approach to dealing with labor dislocation. Significant changes in labor structure need to happen inter-generationally, not intra-generationally.
One of the lessons from the prelude to WWII is to be careful about trade imbalances, as they can breed instability and radicalism. During the 1920s the US enjoyed huge trade surpluses with Europe, which caused all manner of monetary and labor dislocation in Europe. Worse, the US wasn't content with this surplus, so similar to modern China they erected additional barriers to imports to try to have their cake and eat it, too. These effects were amplified by the gold standard, which accelerated deflation and unemployment in Europe, and accelerated (stock market) inflation in the US. And of course all these ill effects were amplified again for Germany.
Toward the end of the 1920s and during the 1930s, the whole system was disassembled as every country, understandably, retreated to lick its wounds. Economic interdependence is critical to maintaining global security, but that interdependence itself isn't self-sustaining. It can fall apart if dislocations aren't managed well across the system. For example, the lessons from the 1990s and early 2000s is, "just go back to college or trade school" is an absolutely horrible approach to dealing with labor dislocation. Significant changes in labor structure need to happen inter-generationally, not intra-generationally.