EU+UK and China have the history of devastating wars at home. USA has not have a devastating war at home since the civil war almost 2 centuries ago. How does this affect their thought process of starting new wars?
EU+UK, China, USA and Russia's war trauma
This came up when watching Talkshows about EU+UK, China, USA and Russia. EU+UK is still horrified by the 2nd world war and want to avoid another war on the continent so much that they hoped and deluded themselves. But they are hesitant in general. Similar things happened after the Great War WW1, when France and British Empire wanted to avoid war as they were still horrified. Russia took a different path and doesn't really fit the bill as they glorified the war and the sacrifices/victims.
China similarly to EU+UK is traumatized by instability, civil wars and Japanese/European invasions. You all likely know the meme "China is whole, then breaks again" "Whenever China has a civil war or famine, 20 Million people die". Chinese have internalized the massive risks of instability and civil wars, and war against strong opponents. It devastates a country that otherwise had 25-36% of the world economy for most of their several millenia of existence, a wealthy country that stops being able to feed their people.
USA had something similar too. After the Civil War, USA was devastated. People really didn't want to have another civil war and in the Great War the population hesitated to support an intervention for Europe. In WW2 it was even more so as US population and many politicians did not want to be dragged into another World War. They isolated themselves until the US administration and Japan triggered the entrance of the US into ww2.
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USA's war trauma in homeland is distant. Imperial Chinese confucian scholars and ministers constantly reminding the Emperors that war and conquests are paid for by the common folk
But in late 20th century after the collapse of USSR, USA is overwhelmingly stronger than other nations military capabilities (even when USSR still existed). In previous wars though USA oftentimes lost the war, they had rather low casualties for losing and those losses were always on the other side of the world, never devastating their homeland. USA also won the cold war against the USSR. And on the first weeks of wars, USA usually get away with almost no casualties until later. All this leads to US politicans and parts of the US population not feeling too strongly about going to war, it is more a monetary or moral question than the fear of total devastation of their homeland.
I dont know much about population sentiments of distant history besides Imperial China. For example in europe, oftentimes the nobility were deciding to start wars, so no clue if the population even had any say on that. In Imperial China the was a saying "heart of the people" which is similar to sentiment of the people, if the people hated the administration and emperor too much, a civil war was about to happen. So Chinese empires couldn't constantly go to war. In Addition confucian scholars and ministers throughout millenia weigh up between funding wars and letting population rest to work on field and grow families. Chinese history in general did not have the idea of "war and conquests will fuel itself" but instead "war and conquests are costs the population has to pay for". The glory of an Emperor or a General is paid for by the sweats and bloods of the common folk on the fields and on the battlefields, was a common trope in literature and poems, and often reminded by ministers and scholars.
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Historical supporting examples for relation between war trauma at home and hesitation to start new wars.
So the question would be if the hesitation to start new wars is present enough in the USA compared to EU+UK and China. The risk difference for the USA as they might feel invulnerable in the late 20th century? Are other historical situation in nobilities and population supporting the idea that recent trauma makes a huge difference for willingness to start wars easily?