Earlier quoted context omitted.
My main concern is that de-globalizing trade will remove a large barrier for real kinetic war. Bombing your economic partner is generally a dumb move, and that has been pretty nice for humanity in the last ~50 years.
I think it won't change much because frankly the peace trade theory has not worked out very well. I think it was first formulated around WW1 and didn't stop it or WW2. Most modern wars don't make financial sense when accounting for everything but they are still fought. Often over stupid reasons. For example Russia invaded Ukraine despite trade partnership with Ukraine and EU. https://en.wikipedia.org/wiki/Democratic_…
I don't think so: for example the Weimar Republic is a counterexample. Or a modern example is the current war between Ukraine and Russia (both are democracies even though in Russia some particular president and party has a lot of influence). Both of these examples show that even in a democratic country under specific circumstances it can happen that a particular group or party can gain lots of power.
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If you want to see another interesting "peace theory", consider the madman theory:
> https://en.wikipedia.org/wiki/Madman_theory
It basically says that if a country has access to atomic weapons, and the president or person in power radiates the image that he is sufficiently "mad" that in case of an aggression against the country they are willing to use them and escalate the conflict into a global nuclear holocaust, other stakeholders will strongly attempt not to upset this country, i.e. seek more peaceful and diplomatic solutions with this country.
This theory explains well why the USA have not yet invaded North Korea and are hesitant to invade Iran.