While developed countries are angst-ridden over the problem of illegal immigration by unskilled workers from developing countries, a different set of concerns has surfaced in Africa.
In particular, the legal outflow of skilled, and even more importantly, highly skilled, people to developed countries.
This outflow is supposedly a new and damaging "brain drain", with rich countries actively luring away needed skills from poor countries.
The fear is misplaced. At the outset, we have to distinguish between "need" and "demand". Yes, many African countries need skills. But they are unable to absorb them, owing to several factors associated with economic backwardness.
In India in the 1950s and 1960s - a time when many professionals were emigrating - working conditions were deplorable.
Bureaucrats decided whether we could go abroad for conferences. Heads of departments carried inordinate power. So, no surprise, many of us left. Hindus may believe in an infinity of lifetimes, but we maximise our welfare in this one, just like everyone else.
Besides, simply holding people back, even if feasible, would do little for their countries.
The "brain" is not a static concept. Trapped in Kinshasa, under appalling conditions, the brain will drain away in less time than it takes to get to New York.
Moreover, keeping people at home is easier said than done. In many poor countries, except those such as India, which has now developed superb educational institutions, the brightest citizens receive their education abroad.
The challenge, then, is to prevent them from staying there and settling down. South Korea, although not poor, faces the same problem.
But, in any event, emigration restrictions today would violate a human right enshrined in current international treaties. But would immigration restrictions work instead, as proposed by some developed-country organisations, which worry about a brain drain?
There are difficulties. Could we really say to a Ghanaian doctor that she must return to her country while an immigrant Russian doctor is allowed to settle down and start a new life? This is likely to run foul of anti-discrimination principles and constitutional provisions in countries like the US.
The proper response to the outflow of skilled manpower from poor countries, especially those in Africa, is to be found in a different direction.
Given that outflows of skilled workers cannot be restricted - and, indeed, should not be - we must devise institutional mechanisms to work with it. This means adopting a "diaspora" model, which implies four policy proposals.
First, stop crying over the fact that the diaspora is not returning home.
Instead, nurture the loyalty of professionals settling abroad, so that they assist their home countries in a variety of ways.
Thus, they may be offered voting rights. Restrictions on investment and land purchases can be dropped. And immigration experts like me have proposed since the 1970s that schemes be developed to enable the academic diaspora to run workshops aimed at bringing teachers up to the best international standards.
Second, while the diaspora should be integrated through more rights, its members also ought to accept obligations that put them on an equal footing with those who remain behind. I suggested in the 1970s that a tax be levied on citizens abroad.
Nicknamed the "Bhagwati tax", it is of course "the American way": US citizens and permanent residents abroad, like those at home, must pay federal taxes.
Third, because skills are necessary for nearly all activities in most of Africa, here and now, we need to organise ways to supply such skills to these countries.
I have long argued that, because many in rich countries are retiring while still in sound health, and because altruism increases with age, we could organise a "grey Peace Corps" of senior citizens to share their skills in countries whose own trained professionals prefer to settle abroad.
Finally, foreign aid should be used to expand training for Africans in all the essential fields in rich countries such as the US, the UK, France, and the Netherlands. They would add to the diaspora, while a grey Peace Corps would help to fill current needs.
When development has taken off, and conditions have improved sufficiently to attract people back to their homelands, the hugely increased diaspora would indeed return, as they have done in India, South Korea and China.
Together, these policies would benefit Africa both immediately and in the long run. Sentimental handwringing over the so-called brain drain, and foolish attempts at restricting people's mobility, will not.
Jagdish Bhagwati is the professor of economics and law at Columbia University and senior fellow in international economics at the Council on Foreign Relations. He recently edited, with Gordon Hanson,Skilled Immigration Today
* Project Syndicate