Migration or mobility across borders is nothing new. People have been migrating from time immemorial - all throughout history. Countries such as Australia, Canada, New Zealand and the USA have been created through immigration.
Yet in an era of globalization when most factors of production are integrating across borders, there is very limited mobility of people and labour across borders. This has happened with the emergence of nation states which jealously guard their borders to keep non-nationals out. The right to leave any country including ones own, and the right to the return to the home country are universally recognized human rights. But there is no corresponding right of admission to a third country since no country has surrendered that right under any international treaty - this is the principle of state sovereignty (except to a limited extent in the European Union for EU citizens). States have the final decision on who will be admitted, who will stay, who will work and who should leave. Thus the human right to leave the home country loses much of its value if people cannot enter another country.
Here the logic of the free market forces - supply and demand - does not seem to apply. A global labour market is still a very distant goal.
