THEY enter the United States mainly at night. Many travel on foot, wading the Rio Grande into Texas or dodging between mesquite clumps in the Arizona desert. Others curl up in the trunks of cars entering Vermont from Canada, or huddle in small boats coasting silently into remote Florida beaches. Some will be caught and expelled (often to try again the next night). Most will go undetected, and soon will have disappeared into any of a thousand American communities, where they will take jobs that, however lowly, pay more than they could hope to receive in Mexico, or Colombia, or Haiti, or Poland.
They are part of the vast flood of aliens -- called, alternatively, ``illegal,'' ``undocumented,'' or ``uninvited'' -- who each year enter the US in violation of the nation's immigration laws.
Although stepped-up patrolling by the US Immigration and Naturalization Service (INS) has resulted in increased apprehensions of illegal aliens in recent years, most experts agree that only a small percentage of entering illegals is stopped. Swelling population of illegals
The majority that evades INS agents swells what is already a large population of illegal aliens living in the US. Estimates of that population range from 2 million to 12 million; experts differ over the number, but they generally agree that its growth has accelerated in recent years.
The US has lost control of its borders, and a widespread (though by no means unanimous) consensus had formed that something had to be done to regain control. The ``something'' is the Immigration Reform and Control Act of 1986, passed by Congress on Oct. 17.
The new law is controversial. Two previous Congresses failed to overcome opposition to the bill before adjourning, and it was pronounced dead in the 99th Congress as recently as last month. Yet the immigration reform that appears to make no one completely happy -- the bill that some call a ``mess,'' a ``hodgepodge,'' or a ``can of worms'' -- revived and passed both houses of Congress with comfortable margins.
``I guess the feeling [in Congress] was that it was time we looked at the general intent of immigration reform and did something about it,'' says Lawrence Fuchs, a professor of American civilization and politics at Brandeis University, and former director of President Carter's Select Commission on Immigration and Refugee Policy.
``No bill will be just the way any of us would want it,'' Professor Fuchs adds, ``but it's a start.''
Here is what the law provides:
For the first time, the United States will impose employer sanctions designed to cut off the economic magnet for illegal immigrants. Employers will be required to ask for a job applicant's proof of citizenship or legal residency. Those found employing undocumented aliens will be subject to civil penalties of $250 to $2,000. Penalties for subsequent offenses climb to $10,000, with criminal penalties, including imprisonment, authorized in cases of a proven ``pattern of practice.''
The law also offers amnesty, or legal residency status, to aliens who have resided continuously in this country since Jan. 1, 1982. Aliens who worked here in agriculture for at least 90 days between May 1985 and May 1986 can become lawful temporary residents, and in two years permanent residents eligible for ultimate citizenship.
The federal government will appropriate $1 billion for each of the next four years to reimburse states for providing welfare, health care, and education to illegal aliens who become permanent residents.
The Justice Department will establish a new office to investigate claims of discrimination in job hiring that result from the new law.
The law authorizes a doubling in the INS enforcement budget. The service will use the increase both to enforce the new employer sanctions and to beef up its efforts to stop aliens from entering the country illegally. Will reform package work?
What does it all add up to?
The new law will be either a ``turning point'' in reducing illegal immigration or a disaster, depending on the government's commitment to enforcing it, says Roger Conner, executive director of the Federation for American Immigration Reform (FAIR).
That organization expects undocumented aliens without grounds under the new law for remaining in the country to adopt tactics aimed at circumventing the legislation. These include, FAIR predicts, a flood of lawsuits opposing the employer sanctions as discriminatory and huge increases in claims for refugee status. And like some members of Congress who opposed the bill, FAIR foresees a ``potential for chaos'' as the government attempts to deal with an expected avalanche of fraudulent claims of residency or employment.
Most experts, citing recent examples from European countries, agree that employer sanctions can slow the influx of illegal aliens. The key, they say, will be whether the country truly has the will to enforce the new law. They wonder how diligent federal enforcement will be in the face of opposition from employers who have become used to a ready supply of inexpensive and hardworking laborers, not to mention resistance from illegal aliens themselves.
``Our reasons for admitting illegal aliens have never been altruistic,'' says Sidney Weintraub, an economist at the Lyndon B. Johnson School of Public Affairs at the University of Texas at Austin. ``We do it because Americans benefit from it.''
Although some researchers, such as Rice University's Donald Huddle, argue that illegal aliens are increasingly taking skilled jobs from Americans, others say that too many businesses profit from the illegals' presence for there to be the kind of national commitment needed to deter illegal immigration.
``I think it will be a lot like the 55 miles-per-hour speed limit,'' says Ken Roberts, an economist at Southwestern University. ``I don't think most people in the West feel too bad about breaking that law, and they won't about hiring an illegal alien, either.''
The sheer magnitude of enforcement requirements has some experts doubting the sanctions' effectiveness. ``Successful enforcement means going after hundreds and hundreds of small employers,'' says Kevin McCarthy, a senior demographer with the Rand Corporation in Santa Monica, Calif. ``It's always possible, but it will be difficult, and very expensive.''
``I'd expect a considerable black market in low-wage labor to develop,'' Mr. McCarthy says. ``[Employer sanctions] will have an effect, but they won't stop immigration.''
Dr. Weintraub of the University of Texas says a ``brisk traffic'' in false documents could lead to calls for more foolproof documentation, such as the universal work-eligibility cards suggested by the Commission on Immigration Policy. Although Americans have traditionally been ``very suspicious'' of that kind of universal identifier, he says, a perception that employer sanctions are not working could cause reconsideration.
Rice's Dr. Huddle expects ``a series of steps'' to clamp down on illegal aliens who enter the country other than by sneaking across its borders -- through misuse of visas, for example, or by fraudulent marriages to American citizens.
``I think more of us are finally asking ourselves the question, `What do we want to achieve through immigration, and what's the best system for achieving those goals?' '' Professor Fuchs says. ``Nobody's saying we should shut the door. . . . That doesn't mean the extension of opportunity should be boundless, but surely we haven't reached the limit yet.''