Your final, absolute, sentence (use of “always”) hardly is hyperbole. The existence of and distribution through the Pamir Knot is demonstrably critical in the development of Homo sapiens and its dissemination of its self, its early cultures and its innovations - indubitably including such societal building blocks as language, hunting and possibly primitive agricultural practices.
The seemingly endless steppes’ ease of travel therethrough - ease compared to mountainous and broad-river lands - means that large masses of humans have been traversing…”invading” being the way the extant observer would consider that…not for thousands of generations but tens of thousands. That’s as good as “always” as it gets. And it is not much of a stretch from there to consider such as being in their genes. Most absolutely in their “cultural genes”, define that how you may.
Zooming to the immediate present - let’s say, only the most recent millennium - brings me to this statement of yours…(cont’d)
My partner has an MS in Psychology and works with people who have trauma. Usually people who are in the legal system because of it. One thing she has been studying lately is epigenetics. Studies on mice have found that if a mouse is traumatized in some way, their children will react with fear at the same sort of trauma the first time they encounter it. The grandchildren will too.
It sounds like 19th century psychbabble, but it's proving to be true. Studies on human populations are more difficult to pin down because humans can't be raised in a lab with their whole lives controlled, but it appears humans can suffer from it too. She has a friend who is Jewish and has lived her entire life in San Francisco. Her parents were Holocaust survivors and the recent war in Israel has caused her to completely melt down. Normally she's a "kumbyya" type who is all for inclusion of everyone, but since Oct 7 she has become rabidly anti-Arab.
There is probably some epigenetic trauma in the Russians too. The German invasion of 1941 is fading from living memory, but there are quite a few Russians who are children of the war generation still around. The geographical vulnerability of their country and the trauma it has caused through the centuries may be baked into their DNA now.
That policy seems to resonate in America with those that are struggling to get by.
There has always been an undercurrent of isolationism within the US. Non-Americans often comment about how provincial American tourists can be in their countries.
Geography contributed to this. Thanks to the resource base of the US and it's location, the US was able to build up into a superpower without really needing to interact with the outside world to the degree most other world powers had to. Both Russia and the United States conquered a continent, but Russia's task was subduing a somewhat large native population in Asia along the way. The Americans only had to conquer the land, the continent they were conquering was sparsely populated by a people with a dramatically poorer technological level.
The United States enjoys having a significant part of the country in the sweet zone for farming, being rich in other natural resources, and having a natural water transportation system that is the best in the world. The Ohio/Missouri/Mississippi river system drains the interior of the continent and most of those rivers are navigable throughout. That allowed farmers deep in the interior to get their goods to the ocean port at New Orleans before railroad existed. Then the barrier islands that line most of the south and east coast allowed a salt water inland waterway to the east coast cities. The Columbia and Sacramento rivers in the west also allowed goods to travel to ocean ports. Even today 40% of the grain exported from the US comes down the Columbia River by barge and is loaded onto ships in Portland.
Canada is stuck with the Canadian Shield which is poor for farm land as well as harsher winters and only the man-made St Lawrence Waterway as a route to the sea. Mexico also lacks a river network.
So the US has always enjoyed safety to develop along its own lines more or less free of interference from the outside world. The immediate neighbors were never a military threat after 1812 and the rest of the world had no hope of becoming a military threat.
The US became a somewhat provincial place which was concerned about its own internal issues much more than they were concerned about the rest of the world because the rest of the world was no threat. The development of nuclear weapons changed that, but almost 200 years of isolation is embedded in the national psyche. Especially deep in the interior.
The coasts tend to be more aware of the outside world and have more interaction with them. That's one of the factors dividing the country politically. The people the interior call the "coastal elites" are more outwardly focused and pay more attention to what's happening in the world whereas the people of the interior while still knowing some of what's happening in the world, they have historically been less interested in what the world outside the US borders have to offer.
One party has played on that isolationist streak among their constituents and amplified it to 11. After 70 years of the US being a part of the world because it was the "free" world's stabilizing force, those same people are now in favor of the US taking its marbles and going home.
When a country is the world's biggest economy, it can't afford to be isolationist. If the US had taken a leading role after WW I like it did after WW II, WW II may not have happened. Britain and France didn't want the US in a leading role and between US not being used to being in the spotlight and Woodrow Wilson getting very ill during the peace talks, the US became hyper isolationist instead of stepping up which left a power vacuum. Britain and France were still strong powers, but the war had taken a lot out of both countries and they were unable and unwilling to stop Hitler in time.
Putin's propaganda machine saw this strain of isolationism growing in the US and plugged into the forces driving it, amplifying it even further. Putin is poor when it comes to military matters, but he is very good at cultivating psi-ops. Russian propaganda has found fault lines in the politics of many western countries and amplified them.