Look closely at the globalisation debate and you will be astonished at how few of the participants, except for right-wingers such as Patrick Buchanan, talk about international migration. The buzz is all about trade, multinationals, and short-term capital flows. Yet international migration has become one of the central issues of our time.
Historically, countries felt they had the right to treat immigrants as aliens, without rights and barely deserving of our kindness.
But national sensibilities have shifted. Greater respect for the rights of people moving across borders, whether they are skilled or unskilled, legal or illegal, voluntary or forced, reflects the remarkable surge in the human rights movement in the last quarter of the 20th century and the associated growth of lobby groups such as Human Rights Watch that fight to extend the rights of migrants.
When oil prices quadrupled in 1973, west European economies went into a tailspin and experienced significant pressure on employment. But even the tough-minded Germans could not bring themselves to expel the foreign workers, the Gastarbeiter, despite their contractual right to do so. As Max Frisch, the Swiss novelist, remarked of the phenomenon: "(They) imported workers but got men instead."
Similarly, last year, when Tony Blair and Jose Maria Aznar, his Spanish counterpart, proposed that the European Union should withhold aid from countries that did not effectively stem the outflow of illegal migrants and asylum-seekers to the Union, they were greeted by outrage.
Clare Short, then Mr Blair's outspoken minister for development, joined the chorus of condemnation, describing the proposal as "morally repugnant" and ensuring it was swiftly buried.
The political mood has also changed dramatically in favour of accommodating, rather than rejecting, the claims of migrants to better treatment. As the size of different ethnic groups in various countries has grown, they have increasingly provided protective cover to new, illegal immigrants. And as immigrants have changed nationality and got the vote, they have acquired increased political clout. This and the changing popular sensibility have helped rein in nationalist politicians' instinct to take strong action against illegal immigration.
President George W. Bush, prior to the September 11 tragedy, offered an amnesty to illegal Mexican immigrants, in a transparent attempt to win over the Hispanic vote. The fact that his offer was confined to Mexicans broke the principle of non-discrimination enshrined in the 1965 Immigration and Nationality Act. Similarly, California has accepted the demand by the Hispanic community to allow illegal immigrants, who are largely Mexican, to get driving licences: a humane grant of a right, dictated by ethnic politics, that would have been unthinkable only a decade ago.
International migration still looks small in scale: approximately 175m people, amounting to only 3 per cent of the world's population, have moved across borders to live for more than a year. Historians argue that migration was more common during the 19th century, when as much as 10 per cent of the world's population moved. However, the bulk of that migration was from the old countries into areas of new settlement like Australia.
These movements were seen at the time as benign (though they created massive adversity for the indigenous populations who had no voice then). Today much of the migration is from the poor to the rich countries, which has created its own tensions and problems.
This pattern of migration from poor countries today consists, first, of unskilled people, often migrating illegally, and, second, of legal skilled migrants. Rich countries are busy changing their immigration policies to weight them in favour of skilled immigrants, even as they try to restrict the inflows of the unskilled. This has led to an asymmetry. The supply of unskilled immigrants currently exceeds demand in the rich countries. This feeds illegal immigration and a flood of false asy lum claims. By contrast, rich countries' demand for skilled immigrants exceeds supply - and in the US businesses are even calling for increased quotas for skilled immigrant workers - and the poorest countries worry about losing their relatively small number of skilled nationals. The flood of illegal unskilled migrants into rich countries and the "brain drain" of skilled citizens from the poorest countries are two of the most critical current issues in international migration today.
These problems, as well as issues such as international trafficking in women and children, have highlighted a gaping hole in the international institutional architecture. We have only a fragmented set of institutions to deal with flows of humanity. The International Labour Organisation looks after workers' rights. The United Nations High Commissioner for Refugees deals with forced migrants. The World Trade Organisation, under its services agreement, manages the temporary access of professional and semi-professional workers - from builders to doctors - to other countries. The International Organisation for Migration is a cross between a consulting body and an altruistic group. Besides, its status is not defined by a treaty. Indeed, we do not have a treaty-defined "World Migration Organisation" (WMO) that could oversee the whole phenomenon, according to internationally agreed objectives and procedures.
It would have been hard to justify a WMO when migration issues barely made it on to the charts. But today they are a central issue for many countries. Despite growing bilateral and regional treaties, and some multilateral norms governing migration - such as the 1990 UN convention on the protection of the rights of migrant workers and their families - it would be overambitious for a WMO to start by defining rules for member countries. It could, however, begin by consolidating the different protocols and norms that have emerged to govern the migration question. Over time, these could be turned into ratified conventions. A new WMO could also carry out impartial reviews of the migration policies of member countries, nudging the not-so- enlightened states towards better practice by juxtaposing their records against those of more progressive countries, the way the WTO uses its trade policy review mechanism to influence member countries' trade policies.
In this way, we might realistically begin to fill the last remaining gap in the institutional architecture that covers our interdependent world.
The writer is a professor of economics at Columbia University and senior fellow at the Council on Foreign Relations.