There could be no place more fitting for a lecture on international flows of humanity than this great university, located as it is in a city which has been the archetypal success story of international migration.

And you could not have chosen a better person to name it after than Emma Lazarus, whose unforgettable lines are inscribed on the base of the Statue of Liberty, the Mother of Exiles. Just in case you have forgotten them, they are printed in your program!

While Emma Lazarus´s immortal words promised welcome to the tired, the poor, the wretched, and the huddled masses yearning to be free, another American poet, Walt Whitman, spoke of the vibrance and vitality that migrants brought to the new world. He called New York the “city of the world” –because, he said, “all races are here, all lands of the earth make contributions here”.

How right he was –and still is. Today, more than one in three inhabitants of New York City was born outside the United States. The city boasts communities of 188 different national origins –only three fewer than there are member states in the United Nations –and 47 per cent of them speak a second language at home.

New York, in other words, is a brilliant success story of migration, as are many other cities all around the world today. In fact, in the year 2000, some 175 million people, about three percent of the world's population, lived outside their country of birth –more than at any other time in history.

Of these, around 16 million were recognized refugees - people who did not choose to leave home but were forced to. Another one million were asylum seekers –people who claimed to be refugees, but whose claims were in the process of being verified.

The remainder, some 158 million, were deemed international migrants –that is, people who have chosen to move.

So much mobility and diversity should be cause for celebration. But migration also gives rise to many problems, leading people to ask:

Can we absorb large numbers of new people?

Will they take our jobs or absorb our social services?

Are they a threat to our security, our way of life or our national identity?

These are understandable concerns, and they must be answered. The answers are not easy. But I have come here today to say that they do not lie in halting migration –a policy that is bound to fail. I say the answer must lie in managing migration –rationally, creatively, compassionately, and cooperatively.

This is the only approach that can ensure that the interests of both migrant and host communities will be looked after, and their rights upheld.

It is the only approach that can effectively address the complex issues surrounding migration –issues of human rights and economic opportunity, of labor shortages and unemployment, of brain drain and brain gain, of xenophobia and integration, of refugee crises and asylum seekers, of law enforcement and human trafficking, of human security and national security.

And it is the only approach that can, if we get it right, bring advantages to all parties –sender countries, countries of transit, host countries, and migrants themselves.

Many migrants, while not literally forced to move, choose to do so under duress. They see no opportunity at home to improve themselves, or perhaps even to earn a living at all. Their departure may be a source of sadness for themselves and their families, and also a loss for their home countries –often poor ones, which could have benefited from their talents. They are usually not free riders looking for an easy life, but courageous men and women who make great sacrifices in search of a better future for themselves or their families.

Nor are their lives always to be envied once they have left home. They often face as many risks and unknowns as they do hopes and opportunities. Many fall prey to smugglers and traffickers on their journey, and many more face a surly welcome of exploitation, discrimination and prejudice once they arrive. Many have little choice but to do dirty, dangerous and difficult jobs.

Undoubtedly more needs to be done to create opportunities in poor countries for individual self-improvement. This is yet another reason why we must strive harder to achieve the Millennium Development Goals, including by forging a global partnership for development which, among other things, gives poor countries a fair chance to compete in the global market.

But migration itself can also be part of that global partnership –part of the solution to economic problems, not only in sender countries, but also in receiving ones.

Sender countries benefit enormously from migrant remittances. They bring not only vital sustenance to the migrants' families. They also bring much-needed stimulus to the national economy. Last year alone, migrant workers in developed countries sent at least 88 billion dollars back to their countries of origin –more than those same developing countries received in official development aid. These amounts are growing fast.

Emigration also relieves the pressures of overpopulation and unemployment, and in time endows sender countries with an educated diaspora who often bring or send home new skills, products, ideas and knowledge.

In short, migration is one of the tools we have to help put more of the world's people on the right side of –and ultimately, to eliminate –the vast divides that exist today between poor and rich, and between fettered and free.

Host country economies, too, can reap benefits. After all, the main reason any country attracts immigrants is its need for their labor. They perform many services that the host population is eager to consume, but is either unwilling or unable to provide for itself –from highly skilled work in research or information technology to less skilled jobs tending fields, nursing the sick and elderly, working on construction sites, running corner shops that stay open all night, or looking after children and doing housework while parents are out pursuing careers.

Increasingly, as birthrates in many developed countries fall, and populations age, immigrant labor, taxes and spending are becoming a demographic and economic necessity. Without them, pension schemes and health-care systems will be in danger of collapse. While immigration may not by itself be the answer to all these challenges, there is no answer to them that does not include immigration.

So migration has a demand as well as a supply side. Migrants are rational human beings who make economic choices. Up to now, rich countries have been far too comfortable with a policy framework that allows them to benefit from immigrant labor, while denying immigrants the dignity and rights of a legal status.

That is not good enough. Let us remember from the start that migrants are not merely units of labour. They are human beings. They have human emotions, human families, and above all, human rights –human rights which must be at the very heart of debates and policies on migration. Among those rights is the right to family unity –and in fact families reuniting form by far the largest stream of immigration into North America and Europe.

The more we try to deal with migration simply by clamping down on it with tighter border controls, the more we find that human rights are sacrificed –on the journey, at the border, and inside host countries.

Few if any states have actually succeeded in cutting migrant numbers by imposing such controls. The laws of supply and demand are too strong for that. Instead, immigrants are driven to enter the country clandestinely, to overstay their visas, or to resort to the one legal route still open to them, namely the asylum system.

This experience shows that stronger borders are not necessarily smarter ones. And it shows that they can create new problems of law enforcement and lead almost inevitably to human rights violations.

The gravest violations come at the hands of smugglers and traffickers. Smuggling occurs with the complicity of migrants, usually because they can see no legal route to migrate. Trafficking is a modern form of slavery in which migrants are coerced and exploited. All too often, people who initially collaborate with smugglers later find themselves in the hands of traffickers.

Asylum processes, meanwhile, become clogged with doubtful cases, with the result that bona fide refugees are often detained for long periods. They are often denied the rights accorded to accused or convicted criminals –and, when free, they are objects of suspicion and hostility. This, in turn, undermines support for migration in host countries –despite the fact that many of them need migrants.

Those who manage to get in, or stay, illegally become acutely vulnerable to exploitation. If they attempt to assert their rights, they can be met with a threat of exposure and deportation. Migrant women and unaccompanied children are especially vulnerable to physical, psychological, and sexual abuse, sometimes involving the risk of infection with HIV/AIDS.

I am not suggesting that all these problems could be solved at a stroke simply by lifting all restrictions on migration. It is vital for states to harmonize their policies and maintain networks of cooperation and information sharing on smuggling and trafficking routes and trends, and on effective practices in prevention and assistance.

Nor do I suggest that a society can be expected to forego any process for deciding which immigrants it will accept, and how many at a time. But I do say that those decisions need to be positive as well as negative.

And I say here, in the United States, that while I understand this nation's need to ensure that those who come here are not a threat to homeland security, it would be a tragedy if this diverse country were to deprive itself of the enrichment of many students and workers and family members from particular parts of the world, or if the human rights of those who would migrate here were compromised.

I also believe that states need carefully thought-out policies for integrating immigrants who are allowed in. Since both migrants and host societies stand to benefit from successful integration, both must play their part in making it happen.

It is reasonable for societies to expect those who would become citizens to share certain basic values, to respect the law of the land, and to develop fluency in the local language, with assistance if they need it.

For their part, host societies must have effective anti-discrimination legislation and procedures, reflecting international standards and obligations, and should also take measures to promote appreciation of cultural diversity among all their citizens and residents.

But laws and policies are not enough. Leadership is vital too. All national leaders should be conscious that any form of discrimination against immigrants is a regression from the standards for a just society enshrined in the Universal Declaration of Human Rights and the binding treaties that derive from it.

Many people, in government and academia, in the private sector and in civil society as a whole, are showing the leadership that is needed to combat xenophobia and stigma. I salute them for it. But I am also disturbed by the vilification, in some quarters, of migrants –particularly of asylum seekers –often in an effort to achieve political gain.

Many of those vilified have fled their homelands in fear of their lives. States have a legal obligation not to return them to danger. They must establish fair procedures to determine the legitimacy of asylum claims. If, in extreme circumstances, asylum seekers must be detained, certain minimal standards must be provided, and enforced, to ensure respect for their human dignity and human rights.

The international regime for protecting migrant workers, set out in a host of human rights conventions that are either regional in scope or confined to particular categories of workers, should be made applicable to all categories of migrants, both regular and irregular, and to members of their families. Many states have recognized this need.

Recently, a step forward was taken with the entry into force of the International Convention on the Protection of the Rights of All Migrant Workers and Members of their Families –the bill of rights for migrant workers and their families in their new home countries.

This step was important. But it was not enough. So far, only sender states have ratified the Convention, which means that it will have little practical effect. I call on all states, and in particular receiving states, to ratify the Convention, so that the human rights of migrant workers are protected by law.

The Migrant Workers Convention is but one instance of the efforts that are being made to address the issue of migration at the global level. But despite these efforts, consensus is lacking on many of the principles and policies which should be applied to the governance of international migration.

Internationally, we are not well organized to forge that consensus.

The United Nations does play an important role in dealing with many aspects of migration, and a leading role in helping refugees through the office of the High Commissioner. The International Labor Organization gives a voice to organized labor, and sets standards for fair labor practices, in conjunction with governments and the private sector. Outside the UN system, the International Organization for Migration facilitates the movement of people, at the request of member states. UN agencies and the IOM have come together in the Geneva Migration Group to work more closely on this issue.

But we still lack a comprehensive institutional focus at the international level that could protect the rights of migrants and promote the shared interest of emigration, immigration and transit. No single agency works systematically across the whole spectrum of migration issues, and there is no complete legal framework in place to deal with this quintessentially global phenomenon.

I do not pretend that we can achieve such a framework overnight. And we should not await it before increasing bilateral and regional efforts. I am heartened by the efforts of some States –particularly those of the European Union –to find ways of coordinating their actions and harmonizing their policies.

Yet more and more people are coming to the conclusion that we also have to address this issue globally. Doing it regionally or bilaterally is not enough. I particularly welcome the decision taken by a core group of Member States from both North and South to form a Global Commission on International Migration to deepen our understanding of this issue and to make recommendations for improving international cooperation.

The Commission will be have two distinguished co-Chairs in Jan Karlsson of Sweden and Mamphela Ramphele of South Africa. It has my full backing, and I hope it will receive support from states in all parts of the world and from institutions like yours. Most of all, I hope it will help us approach this issue creatively and cooperatively.

As the Commission's work proceeds, there are many questions I believe it should be asking, and that the rest of us should be asking too. For instance:

Can greater cooperation be built between sender and receiver countries?

Have the benefits of short-term and long-term temporary immigration been fully explored?

Could more be done to work with the laws of supply and demand rather than against them?

Might financial methods of discouraging illegal migration be more effective and more humane than some current practices?

What are the best ways to speed up the integration of immigrants into host societies?

Could more be done to harness the potential of migration as a force for development?

Can developing countries do more to maintain contact with their emigrants?

No doubt there are numerous other equally important issues to be addressed as well.

Above all, I believe we must approach this issue with a strong ethical compass. The basic fairness and decency of any society can best be measured by its treatment of the weak and vulnerable. The principle of non-discrimination has become an integral part of the universal moral code, one on which the defense of all other universal values depends. We should keep a firm hold upon it.

The willingness of rich countries to welcome migrants, and the way that they treat them, will be a measure of their commitment to human equality and human dignity.

Their preparedness to adjust to the changes that migration brings will be an indicator of their readiness to accept the obligations as well as the opportunities of globalization, and of their conception of global citizenship.

And their attitude to the issue will also be a test of their awareness of the lessons, and obligations, of history.

After all, many migrants today are seeking to enter countries which not so long ago conquered and exploited their own. And many countries that are now attracting immigrants were until recently major exporters of emigrants.

Along with other countries, the United States falls into a third category –a nation built by immigration, a land where constant renewal and regeneration are essential elements of the national character. That character must never be lost.

And the hope and reality of a new future for those who would migrate must glow brighter today than ever before.

As Emma Lazarus wrote: “Send these, the homeless, tempest-tost to me, I lift my lamp beside the golden door.”