NEW YORK _ The irony of the U.S. immigration debate is that whatever Congress does _ or what the xenophobic groups on the border do _ won't make much difference because hundreds of thousands of immigrants will continue pouring in every year. With or without documentation.

Why? Because the problem of undocumented immigrants is an economic one. While there is a surplus of workers in Mexico and a deficit of workers in the United States, the flow of immigrants from south to north will persist. As simple as that.

In spite of promises made in 2000 by a then-presidential candidate named Vicente Fox, Mexico has not been able to create a million jobs a year. And what do young people who cannot find work in Mexico do? Many migrate to the United States. Without that escape valve, Mexico would be even poorer.

The bad news is that, in the near or distant future, Mexico will still not be able to create the employment opportunities needed to absorb the 1 million workers who enter the job market each year. In other words, Mexico will expel millions of its workers to try their luck north of the border.

Roughly every minute, a Mexican crosses illegally into the United States or enters as a tourist and stays. Every minute. That amounts to half a million a year.

At the same time, the U.S. Border Patrol, every minute, catches two immigrants attempting an illegal crossing from Mexico. In 2005, they made nearly 1.2 million arrests (many of those immigrants more than once).

The result is a kind of filter: For every two immigrants arrested, one immigrant slips by. That is a 33 percent failure rate.

As the world's only superpower, the United States tends to believe it can solve all its problems alone. But that isn't the case.

The United States got into a war in Iraq without U.N. support, and now chaos and death prevail there. It declined to sign the Kyoto Protocol to reduce toxic gas emissions in the atmosphere _ contrary to what the rest of the world did _ and so, global warming manifested itself with a vengeance in the United States in the form of last year's hurricane season, particularly Hurricane Katrina. It is the same thing with the immigration issue.

The United States believes it can control its borders without any help. But it can't. To do that, it must have the cooperation of Mexico and other Latin American countries.

The issue is simple. As Willi Chirino's song goes, immigrants keep coming. So, it should be made easier for them to register on the border _ or at U.S. consulates in Tijuana, Monterrey, etc. _ before they take the terrible risk of crossing with a "coyote" through rivers, deserts and mountains. (Last year, 464 immigrants lost their lives trying to cross illegally.)

Even after the May 1 boycott and marches _ and I witnessed an impressive one here in this city _ there is still a counterculture that wants to limit immigrants' rights. But the protests have already made their mark. Thanks to massive media coverage, no one in the United States can say he's not aware of immigrants' huge contributions to the country or of their precarious conditions. Nor of the necessity to change the current inefficient immigration laws.

In the next few days, the Senate will have a chance to legalize the 12 million undocumented immigrants who are already here, and to grant visas to the half million who annually arrive without documentation.

This is a difficult step, I know, but it's realistic. Besides, it is good for the United States: Immigrants fill the jobs Americans won't take, they pay taxes, create jobs, control inflation and pay for the retirement of a rapidly aging population. In a nutshell, they are big business.

If the senators don't do it, if they yield to anti-immigrant pressure or come up with a decision that appeases the most conservative and least informed voters, they will surely miss a historical opportunity to resolve a problem that has been growing since 1986.

Moreover, without the United States knowing who resides in the country and without controlling its southern border, the fight against terror becomes considerably less effective.

The conclusion: For the United States to seriously limit the entry of undocumented immigrants and retake control of its border, a system must be in place that can realistically grant entry and work permits to people who will try to enter anyway.

Hunger is stronger than fear. So they will keep coming...