... were the days when monarchy was understood to be the default, natural, try-that-first form of government. Democracy has its merits, but protection of national sovereignty is not one of them: laws of property to not apply to a democratically governed country as a whole. Democracy is forever fungible, malleable, break-and-reconstitute political environment.
I understand what you are getting at, but there is (and has been) an even greater fundamental at work. Not even a monarchy or any other gov’t can stay safely behind its own borders if it has something another powerful nation wants, almost irregardless of their respective locations on the globe. (I’ll repeat my hint: 1853. And... The US was the protagonist.)