An often raised objection to secession as self-determination is what about people on the wrong side of border between two new states.
The answer is blindingly simple, if the two new states behave responsibly.
This is what US Assistant Secretary of State for African Affairs Johnnie Carson had to say about today's post-referendum Sudan:
“Controversy over the status of as many as two million southerners in the North and smaller but significant numbers of northerners in the south is another major potential flashpoint that could be greatly diminished if both governments reached agreement on citizenship rights.
“We encourage the North and South to seek ways that guarantee the rights of work, property, residency, and movement for these civilians.
“Actions that might cause people suddenly to become aliens in places where they have established themselves and raised their families will not only be disruptive, but could destroy the mutual trust necessary to accommodate the sovereign needs of each party.”
See the text of his speech to Chatham House on March 7, 2011 here
By way of comparison, this is how the 1976 Vaddukoddai Resolution calling for establshment of an independent Tamil Eelam envisaged the issue:
“Tamil Eelam shall be based on the principle of democratic decentralization so as to ensure the non-domination of any religious or territorial community … by any other section.
“[It] shall be a secular state giving equal protection and assistance to all religions to which the people of the state may belong.
“The rights of Sinhalese speaking minorities in Tamil Eelam ... shall be protected on a reciprocal basis with the Tamil speaking minorities in the Sinhala State."
