With immigration in the news and Washington taking its first cautious steps toward reform, the headlines beg an important question: What exactly is the face of illegal immigration in America today? We know that the current system of immigration, now nearly 25 years old, is outdated and not operating at full capacity. I also strongly suspect that its shortcomings have factored largely in the influx of undocumented immigrants to this country over the last several years. After all, if you don’t have a bachelor’s degree or an immediate relative who can sponsor you, your chances of legally emigrating to the U.S. are very slim. Before we try to fix a broken system, what do we really know, quantitatively, about undocumented noncitizens in the U.S.?

[IMGCAP(1)]For one thing, much public rhetoric takes aim at Mexico for contributing the lion’s share of undocumented aliens to this country. While Mexican nationals do account for a little more than half of the unauthorized immigrants in the U.S. today, they are far from the only country whose nationals are represented. The Pew Hispanic Center reports that about 59 percent of undocumented aliens in the U.S. are Mexican-born, with another 11 percent from Central American countries, 11 percent from Asia, 7 percent from South America and less than 2 percent from the Middle East.

And how many people are we talking about, exactly? According to information collected by the Census Bureau in 2008, undocumented immigrants comprise 4 percent of our nation’s population and 5.4 percent of its workforce. The difficulty in acquiring hard data limits our ability to evaluate the true costs and unintended benefits of illegal immigration. Soliciting information from immigrant communities requires that the undocumented members of those communities incriminate themselves. As a result, attempts to quantify the role that undocumented aliens actually play in American life are spotty at best.

When it comes to approximating the number of undocumented aliens living in the U.S., the prevailing method is to take the number of people who attest to being foreign-born on the census and to subtract the number of known legal immigrants from that pool. Because undocumented aliens have many reasons not to answer the census accurately, corrections are made to the resulting number in an attempt to compensate for lost data. Consequently, the estimated population of illegal immigrants ranges vastly from 7 million to 20 million people. The most commonly used undocumented population estimate is 12 million people.

In 2008, among men of working age, 94 percent of undocumented immigrants were in the labor force, as compared with 83 percent of U.S.-born men. In today’s struggling job market, more current data is hard to gain because, again, it is difficult to gather information about undocumented workers. On one the hand, there is concern that undocumented immigrants take American jobs; on the other, immigrant labor has been, for better or worse, essential to the operation of many successful American businesses.

Undocumented workers performing manual labor may pose a legitimate threat to comparably skilled American-born workers, although they have remained a reliable boon to U.S. employers. There are other concerns about the strain that undocumented immigrants may place on public services, but that strain is countered by the scores of immigrants who have obtained IRS tax identification numbers to dutifully pay taxes on their earnings. The latter often overpay and seldom file for tax refunds for fear of attracting unwanted government attention.

In the absence of hard data, much of what we think we know about illegal immigration in America is an extrapolation of what we see around us. Depending on one’s own feelings and observations, or even geographical location, one may consider undocumented individuals a scourge on the nation or the disenfranchised persons for whom legal status was not possible under an archaic system. Some feel that undocumented immigrants play an important and underestimated role in the labor pool, while others feel that they pose a serious threat to the American workforce. The immigration debate is an incendiary one, and in the absence of incontrovertible facts, the arguments continue to be fueled by rhetoric and network pundits rather than hard data.

One legitimate concern associated with a large undocumented immigrant population is the risk associated with so many people living in the shadows. With so many people living invisibly, our national security is potentially threatened by unknown vulnerabilities that could be exploited. The immigration system has played its part contributing to undocumented population by setting unreasonably high standards, and now that so many people have resorted to clandestine means of entering the country, deportation would simply be too large an undertaking, not to mention prohibitively expensive.

The ultimate solution to this problem is to update our antiquated immigration laws. While it is understandable to want to attract highly skilled foreign workers, there is clearly a need for blue-collar workers as well. Further, for nationals of many countries, spouses and children of a green card holder (a person who already undertook a long, complicated and expensive process to emigrate lawfully) must wait several years before they can enter the country legally to rejoin their husband and father. The visa backlog is so long that it may very well encourage otherwise law-abiding people to “jump the line” and arrive without authorization. Our immigrant grandparents never jumped through similar hoops and had many of them attempted to emigrate today, the overwhelming majority would have been turned away.

The Obama administration has already recognized the shortcomings of the present system and must facilitate immediate and comprehensive reform in order to fully address the issues at hand. Judging by the reception that met the health care reform and financial regulation bills, it may be a long and protracted fight. Updating and improving the current system, though, remains the only way we can resolve the controversy surrounding undocumented immigration in the U.S. today.

Michael Wildes is a former federal prosecutor, former mayor of Englewood, N.J., and managing partner of Wildes & Weinberg in New York.