Strict borders have only existed for ~100 years, and many were drawn without much regard for the people living there, often constructed with intention of religious segregation, and to maintain europe's global superiority
They run counter to the notion of sovereignty and local agency which we value greatly in the US
The irrationality of strict country borders and heavy migration controls will emerge as a heavy global challenge due to economic and climate migration and aging populations
I don't think we have a good answer for what replaces them, but I don't believe there's enough evidence to state that hasty decisions made after WWI and WWII should forever govern global human freedoms - and we need a better approach than war to renegotiate some of this
Part of the reason this thread and this topic is so fraught is there are many people, like you, who are willingly and confidently lying about history. Strict borders have existed since ancient times. There are physical markers of them all over Europe that are more than 1000 years old. You can see other borders from space. This idea that only in the 20th century did this idea emerge is so wrong that it’s got the history completely and totally inverted. Why make stuff up like this?
Specifically, assuming a succesfully policed border, how did one prove their nationality, if they had such a thing, or their legitimacy otherwise for crossing it?
I will take your word for it either way! Just genuinely curious. How was it all handled before passports and birth certificates and such?
For identity away from people that knew you or your relatives you had to rely on physical letters of introduction from trusted, well know people.
But usually you were proving that you were entering (or leaving) for a legitimate purpose rather than identity exactly. There is a long history of travel documents for this, see https://en.wikipedia.org/wiki/Passport#Antecedents
Worth noting that once urban centers formed travel became the exception rather than the rule. There were traders who traveled trade routes and knew that requirements on those routes but for more exceptional travel you had to rely on these introductory letters in many areas of the world.
Mass migration events were different of course - and were always problematic.
The concept of a passport didn’t emerge out of the ether. If you were traveling on official business, for the state or the military or as a merchant, you’d be carrying papers that said as much. Much of it relied on trust and reputation, and assuming we’re talking about say medieval Europe possibly the signature or word of a Lord. As for enforcement, violence was common.
One of the biggest drivers of strict borders was tax collection: they defined who could collect tax from which subjects. This was a common source of conflict and so anywhere feudalism was practiced strong border definitions were strongly enforced.
It's possible the grandparent is talking more about the idea of limiting travel across those borders. That is a more defensible position but even then it was more about the the costs of enforcement.
Trade routes had very strong border enforcement because the borders were places taxes were collected for example, and there were limits on who could travel various routes.
For example Venice, Genoa and the Ottoman Empire jealously protected European end of trade routes linking to the spice road.
They run counter to the notion of sovereignty and local agency which we value greatly in the US
The irrationality of strict country borders and heavy migration controls will emerge as a heavy global challenge due to economic and climate migration and aging populations
I don't think we have a good answer for what replaces them, but I don't believe there's enough evidence to state that hasty decisions made after WWI and WWII should forever govern global human freedoms - and we need a better approach than war to renegotiate some of this