Can US halt illegal migrants by hosting more 'guests'?

End the presence of illegal Mexicans in the US.

That's the challenge Mexico's President Vicente Fox laid down during his visit this week with President Bush.

While those words and his end-of-the-year timetable took many in Washington by surprise, Mr. Bush has already signalled his own interest in changing the rules for undocumented workers from Mexico and the US employers who hire them.

Whatever policy shifts emerge from the Fox-Bush talks look increasingly likely to center around temporary-worker rules, also known as the guest-worker program. The trouble is, the current program has few defenders - on either side of the immigration debate - and expanding it in a way that legalizes every Mexican worker in the US, which is Mr. Fox's aim, is sure to ignite a firestorm of controversy.

Some analysts are hard-pressed to see how such a program could even work.

The first problem is that US employers in most regions have little incentive to hire foreign nationals who are in the US legally over those who are illegal. Why? There are so many undocumented people willing to work for a relative pittance - and hiring them doesn't require all the bureaucratic hassles of hiring someone through the government guest-worker program.

Furthermore, immigration authorities seldom bust employers for hiring illegals - and there's little political will to change that.

So, many observers say, unless the pool of illegal workers shrinks dramatically - and unless employers are forced to hire only legal workers - illegal workers will still be plentiful and willing participants in the workforce.

"As long as that supply of illegal workers is available, there's little incentive for growers to participate," says Susan Martin, director of Georgetown University's Institute for the Study of International Migration.

Today, official "guest workers" are only a fraction of the immigrant workforce.

In agriculture, which traditionally has employed much of the illegal Mexican labor, only about 44,000 workers were part of the program in 2000, compared with 650,000 immigrants estimated to be working in American fields illegally.

Those workers, moreover, are concentrated in the Southeast, which is farther from the Mexican border - and thus hasn't had the same access to the large pool of illegal workers.

But there are signs the program could catch on, as evidenced by the recent growth in numbers of participants. In 1987, for instance, roughly 13,000 agricultural guest workers received visas. By 1997, the number had risen to 21,000. In 1998, it was 28,000.

This year, experts estimate that perhaps 60,000 visas will be issued. (Currently, the US cap on agricultural workers is 66,000.) That's evidence that Mexicans - who take the majority of agricultural visas - are willing to participate. "They would rather have the certainty of getting paid and the safety of not having to sneak across the border," says Dimitri Papademetrious, co-director of the Migration Policy Institute in Washington.

There is no cap, however, on nonagricultural workers - such as people working in hotels and resorts, as nannies, and on construction and landscaping sites. For nonagricultural guest workers to be admitted to the US, employers must show that such workers are needed to meet temporary or seasonal needs in positions for which qualified Americans are not available. Both the job and the employer's need for help must be temporary. (A third category allows for skilled workers - engineers, accountants, computer programmers, doctors, teachers - with a bachelor's degree or higher. The cap for this category was recently raised to 195,000.)

So far, neither those who oppose higher levels of immigration nor those who favor it seem enamored of the idea of expanding the guest-worker program.

"We think guest-worker programs don't work because they are unenforceable," says Dan Stein, president of FAIR, an anti-immigration group. He is concerned that the current US-Mexico negotiations will lead to "a rolling amnesty disguised as a guest worker program.

"No illegal is going to get into a guest-worker program now unless he sees a green card at the end of the line," he says.

The Mexican American Legal Defense and Education Fund, meanwhile, opposes the current rules, just as it has opposed every guest-worker program in history.

"Such programs as exist now create an exploitable labor force whose status in the country is wholly dependent on the employer, who can depress wages," says Aisha Qaasim, legislative staff attorney for MALDEF. The group calls for a broad-based reform that addresses undocumented workers already in the US, and provides worker protections, opportunity for longer-term jobs, and legal status.