The concept of Sovereign Right; the right of any
Nation-State; exercised through the Parliamentary representatives of its people; to include or exclude anyone within its borders; was codified and confirmed by the Treaty of Westphalia, which ended the 30 years War in 1648. It stands as the definitive definer of the concept of national sovereignty.
The left is totally against the concept of nations and national borders - has been since the time of Lenin.
From the International Socialist Review:
“Socialists are internationalists. Whereas nationalists believe that the world is divided primarily into different nationalities, socialists consider social class to be the primary divide. For socialists, class struggle—not national identity—is the motor of history.”
The Muslims are also against the concept of nations and national borders. They are also internationalists in that they want islam to rule the whole world. Since Islam is both a religion and a political system, once islam takes over say two adjoining nations, there is no reason for a border between those two nations since values (islam as religion) and laws (political islam) are the same.
A nation is simply a container of shared values and common laws. If two adjoining nations have the identical values and laws, then there are not two nations, but just one.