A United States Border Patrol agent keeps watch. (Eric Thayer / Courtesy Reuters)

U.S. President Barack Obama has made reform of the nation's immigration laws his top priority this year. But to succeed, he will need to overcome the old adage "Fool me once, shame on you; fool me twice, shame on me." The last time Congress passed a comprehensive immigration reform bill, the Immigration Reform and Control Act of 1986, it did not work out quite as promised. Indeed, rarely has a piece of congressional legislation failed as spectacularly as did the 1986 bill. It was intended to hold back a growing tide of illegal immigration into the United States but did nothing of the sort. The population of illegal immigrants in the United States, which was somewhat over three million at the time the bill was enacted, surged to an estimated 12 million by 2008. Today, there are about 11 million in the United States without authorization. The epic failure of the 1980s sowed mistrust between Congress and successive presidents, and persuaded many lawmakers that immigration reform does not deserve a second chance. As Representative Trey Gowdy (R-S.C.), who chairs the immigration subcommittee of the House Judiciary Committee, put it in early February, after listing the unmet promises of the 1986 bill: "Why should we believe you now?"

The success or failure of immigration reform legislation this year will turn largely on how that question is answered. In the Senate, the so-called Gang of Eight -- which includes Marco Rubio (R-Fla.); John McCain (R-Ariz.); Chuck Schumer (D-N.Y.), and five others -- has outlined principles for an immigration overhaul. Obama has done the same, and a small group of House Democrats and Republicans is drafting its own proposal. And there is bipartisan enthusiasm for updating legal immigration laws to encourage scientists, engineers, entrepreneurs, and other highly educated immigrants to settle in the United States and boost a weak economy. Meanwhile, labor unions and the Chamber of Commerce are trying to compromise over a new temporary worker program for less-skilled immigrants that would help farmers and seasonal employers such as hotels and restaurants, while encouraging immigrants to come legally. But none of these efforts will likely fly unless advocates can convince skeptical House Republicans that immigration reform in 2013 will not be like immigration reform in 1986.

THE MORE THINGS STAY THE SAME

On the one hand, there are clear parallels between 1986 and 2013. Then, as now, the most contentious issue was how to discourage illegal immigration. Then, as now, improved workplace and border enforcement were seen as the most important tools. And then, as now, legalization or "amnesty" for unauthorized migrants already living in the United States was seen as the only feasible and humane response.

Like the current effort at immigration reform, the 1986 bill was the product of a long, drawn-out battle involving the White House, Congress, and multiple interest groups, including business, agriculture, labor unions, and immigrant rights groups. The fray lasted more than a decade. Congress first recognized the need to do something about the growing number of unauthorized migrants from Mexico in the early 1970s, but legislative efforts, including a comprehensive bill put forward by President Jimmy Carter, failed to bridge the differences. Congress took the rare step of appointing a special commission of cabinet officials and members of Congress, under the leadership of University of Notre Dame's president, Reverend Theodore Hesburgh, to craft a compromise.

The commission's report, delivered in 1981 to the new administration of President Ronald Reagan, became the basis for the 1986 legislation. It took several more years of legislative battles, primarily over whether employers should be required to confirm employees' immigration status, to find a bill that could pass muster in both the Senate and House. The final product was an unsatisfying compromise between business interests that wanted to maintain a steady supply of foreign labor, and labor unions and law-and-order Republicans who wanted to crack down on illegal immigration. It rested on two pillars. One was that the United States had little choice but to offer an amnesty to those already living illegally in the country. Deporting them would be messy and expensive and risk widespread violations of civil rights. It would also harm the farmers and other businesses that depended on their labor. The other pillar was that the best way to halt illegal migration was to turn off the U.S. "jobs magnet" that lured immigrants north. The 1986 bill, for the first time, made it a criminal violation to hire an illegal immigrant.

Only legalization worked roughly as planned. The Hesburgh Commission had been unanimous in recommending that those unauthorized workers who had been in the United States for several years or longer be permitted to stay, and there was less controversy over the measure than over workplace enforcement. Most lawmakers were persuaded by the argument that wiping the slate clean would allow the government to focus on the task of stopping future illegal migration, rather than on cleaning up the past. Some 2.7 million migrants, most of them Mexican, came forward to seek legal status. Fraud appears to have been widespread, particularly in a special program created to satisfy agricultural interests, though the scale has never been precisely documented. More than one-third of those who gained legal status were farmworkers, a number that was almost certainly inflated by a low bar that only required individuals to demonstrate they had worked at a U.S. farm for at least 90 days per year during the previous three years. Still, legalization was unquestionably good for the migrants. Subsequent studies have found that those who were legalized generally moved to better jobs at higher wages (and higher tax brackets) than those who remained without legal status.

The other pillar -- the promise of tough workplace enforcement and sanctions against employers who hired unauthorized migrants -- was unsuccessful. The employer sanctions had initially been raised by Democrats. They were pushed by trade unions and their allies, who feared that reliance on illegal labor would drive down wages and labor standards for American workers. The agriculture sector and other business groups were adamantly opposed. Latino rights groups and other immigrant advocates were as well, fearing that any sanctions scheme would lead employers to discriminate against legal immigrant workers as well as illegal ones. The result was a weak provision that would have been unenforceable by even a determined administration. In particular, the bill said that the government could impose sanctions only on employers who "knowingly" hired unauthorized workers.

And the Reagan administration was far from determined to enforce the measure, seeing its role as getting government off business' back, not imposing new and expensive mandates. The Hesburgh Commission had also been unable to agree on any single identity document that would prove work eligibility. As a result, the legislation left even conscientious employers the impossible task of thumbing through Social Security cards, multiple state driver's licenses, and other easy-to-forge documents to determine employment eligibility.

Although illegal migration fell for several years after the bill, by the mid-1990s, illegal border crossings again reached record levels. The booming U.S. economy, a lack of legal visa options for lower-skilled workers without family ties, and a series of economic upheavals in Mexico and Central America drew millions northward. Under pressure from states such as California and Texas, the Clinton administration ramped up border enforcement by hiring thousands of U.S. Border Patrol agents and building fences under such optimistically named schemes as Operation Gatekeeper and Operation Hold the Line. For more than a decade, though, the agents were more a nuisance than a genuine obstacle. Surveys in Mexico showed that almost anyone determined enough would eventually succeed in entering the United States.

THE MORE THINGS CHANGE

With the immigration debate again heating up, the basic pillars of reform are largely unchanged from 1986. The bipartisan Senate group and the Obama administration favor continued border enforcement, expanded workplace enforcement, and another legalization for many of the unauthorized immigrants who have come to the United States since 1986. But to succeed, they will have to persuade the skeptics, especially among the Republican majority in the House, that the results will be different this time around.

Improved border security is perhaps the biggest reason why the task is not as daunting now as it was nearly 30 years ago. Over the past two decades, the government has built up what the Migration Policy Institute recently termed "a formidable machinery" of enforcement that has made it far harder to both immigrate to the United States illegally and to remain here without legal status.

In 1986, just 2,000 Border Patrol agents, many on horseback, were supposed to secure more than 2,000 miles of land border with Mexico, as well as occasionally patrol parts of the border with Canada. By 2004, there were around 10,500 agents. Today, there are more than 21,000 -- and they are armed with SUVs and high-tech sensors and aided by aerial drones and nearly 700 miles of border fence. According to a recent U.S. Government Accountability Office study, as many as four out of five illegal border crossers today either are arrested or give up and return to Mexico. Crossing attempts also appear to be way down. The number of apprehensions at the border -- which is a rough proxy for attempted illegal entries -- is at its lowest level since the early 1970s, and just one-fifth of the peak reached in 2001. Those who are apprehended increasingly face more severe consequences, including jail time.

It is also much harder to live in the United States illegally than it was several decades ago. In the 1990s, those staying without papers were rarely found. Those who were discovered and ordered to leave rarely showed up for their scheduled departure. In the aftermath of the 9/11 attacks, though, the realization that several of the hijackers had overstayed visas and were living illegally in the United States triggered a push to identify, jail, and remove unauthorized migrants. For the past four years, approximately 400,000 people have been deported each year, and many state and local police forces are working closely with the federal government to identify illegal migrants.

The biggest enforcement weakness remains in what was supposed to be the silver bullet of the 1986 act -- workplace enforcement. An airtight employment verification scheme would still fall short of perfect, since some people will always work off the books for cash. But the United States' employment verification scheme is hardly airtight. In 1996, Congress created a voluntary pilot program that allowed employers to check new hires against Social Security and immigration records. In 2007, it was expanded into a larger E-Verify program that offers a quick check of new employees against federal records and flags those whose documentation is questionable. More than 350,000 employers are enrolled today; it is mandatory for federal contractors and in some states. But that number is still a small fraction of the country's seven million employers. And even employers who are enrolled cannot be sure that their workers are legal; a phony Social Security card or other identity fraud can defeat the system. Schumer, who chairs the Senate Judiciary Subcommittee on Immigration, has urged the creation of a fraud-proof biometric card, but the idea still faces strong resistance from civil libertarians and conservatives wary of government encroachment.

Despite huge investments that make border enforcement today look far different than it did in 1986, many in Congress are not persuaded and insist on still greater border control as the price for supporting new legislation. In response, the Senate Gang of Eight has proposed "triggers," or enforcement benchmarks that must be met before full legalization would kick in. The Senate proposal states that current unauthorized immigrants could not seek permanent residence in the United States until U.S. land borders are deemed properly secured and a workable system is in place for tracking the entry and exit of those traveling through airports. Obama has pushed back against the vague directive, warning that it could delay for decades any path to citizenship for unauthorized immigrants. Much of the debate in the coming months will be over this issue of what, if any, triggers there should be. But the basic formula -- another legalization in exchange for tougher immigration enforcement -- remains much as it was in 1986.

As was the case after 1986, however, the legislation's strategic compromises could be drowned out by factors well outside Washington's control. In the 1980s, a huge group of Mexican baby boomers was coming of age in a weak Mexican economy and looking north to a vibrant United States. Today, that age group is shrinking and finding more opportunities at home. According to Pew surveys, there has been no net migration from Mexico to the United States in the past several years. But a strong rebound in the U.S. economy could still prove a big magnet, not just for Mexicans but increasingly for other nationalities as well; while the numbers are still fairly small compared with Mexico, the fastest growth in the number of illegal migrants today is from Honduras, Guatemala, and India. Ideally, U.S. immigration policy would make it relatively easy for immigrants to live and work in the United States legally, and very hard to do so illegally. The 1986 bill left a system that for the past several decades has done the opposite. This year may finally offer another opportunity to get it right.