What is the difference between “hard” and “soft” borders?
And Trump was right. There are “shithole countries”. You might not be anywhere outside the USA, but I have seen such countries with my own eyes.
You probably don’t realise that if the borders are opened you will have millions of people from these “shithole” countries going to the USA, they mostly will be people without skills and education.
In 19th century there were natural barriers to travel, today it is very easy with modern transportation.
As for original Europeans who came to the USA without asking permission. Don’t you think the Native Americans would rather they had an ability to stop that? Do you want to repeat the history this time you being in a position of Indian?