Below is my column on the recent controversy over a threatened tariff against Mexico for its failure to stop undocumented immigrants from crossing the U.S. border. Despite the last-minute deal with Mexico purportedly avoiding the tariff, President Donald Trump was back on the weekend threatening “very profitable tariffs” on Mexico. Whatever the purpose of such tariffs, however, they are unlikely to solve our problem with unlawful immigration absent greater enforcement on this side of the border. My point is not to call for wholesale prosecutions. Indeed, the primary concern is not the hiring by families or small businesses, but rather large operations with large percentages of undocumented workers.  If there government truly wants to curtail the undocumented workforce (and that is uncertain), hammering the immigrants at the border or attempting mass deportations is unlikely to succeed. There remains a striking disconnect between the level of enforcement directed at undocumented individuals as opposed to large employers of undocumented persons.

Here is the column:

President Donald Trump has long defined his immigration policies as simply a matter of toughness. Indeed, making the border crossing tougher has been the overriding thrust of his deterrence effort. He has complained to border agents that he would love to see them get “a little rough” but that “when you do all of these things that we have to do, they end up arresting border patrol people.” He even threatened a 25 percent tariff on all goods from Mexico for its failure to prevent people from crossing the border.

Yet, no hardship has deterred millions on this dangerous journey because jobs waits on the other side of the border. To remove that attraction, the government would have to get tough not on migrants but on those who hire them. But that is a tad too tough, it seems, for most immigration hawks. According to a recent study, the Justice Department prosecuted only 11 employers in the entire nation last year. With Pew Research Center estimating that about 11 million undocumented persons are living and working in the United States, the Justice Department is prosecuting at a rate of just one employer for every one million undocumented persons.

Immigration, it seems, is an offense committed solely by undocumented persons. While the president has charged that undocumented workers take away jobs from citizens, neither political party appears eager to deal with those employers who give away those jobs, despite undocumented persons making up an estimated 5 percent of the workforce. In California, Nevada, and Texas, they make up almost 10 percent of the workforce.

Toughness does not extend to those who benefit most from unlawful hiring. There are no federal agents being asked to get “a little rough” with corporate executives. On paper, federal law is clear and tough. It is illegal to hire, recruit, or refer illegal immigrants for hire. It also is illegal to fail to verify work authorization. Knowledge of unlawful hiring can be inferred from the lack of proof or from suspicious job applications.

Moreover, the laws are based on the assumption of enforcement actions that ratchet up punishment to deter repeat offenders. The penalty for every illegal worker rises from $2,000 to as much as $10,000 by the third offense. Knowingly hiring illegal workers can result in six months of jail, while “harboring” such workers can result in up to 10 years in prison. Yet, if there is little enforcement, then the hiring of undocumented persons remains not just a cost of doing business but a small cost in general.

The government continues to publicizes splashy cases, such as the large $5.5 million fine against Waste Management of Texas. Yet, these relatively rare actions pose little threat to most businesses, as shown by the rising numbers of illegal workers in the workforce. Classic economic theory treats the deterrence of crime as the relationship between the rate of detection and the severity of the punishment. If the rate of detection is high, penalties can be low and still achieve deterrence. If the rate of detection is low, the deterrence theory would prompt high penalties.

The curious thing is that this is a federal offense being committed out in plain sight. Certain industries are open recidivists in violation of federal immigration law. As much as half of our farmworkers across the country are believed to be undocumented, while 15 percent of employees in construction jobs and almost 10 percent of fast food and domestic help are also believed to be working illegally. One would think that, at less than a dozen prosecutions of employers, detection rates are virtually zero.

Detection, however, appears quite high, with one out of every two workers in agriculture being undocumented. For a rational actor, the low level of prosecution is an invitation to violate federal law. According to a recent study, only three employers were sentenced to jail out of 11 prosecutions. That puts the rate of prosecution at slightly above cases forharassing golfers in a national park (18 U.S.C. 165 & 36 CFR Sec. 7.96(b)(3)) or attempting to change the weather without notifying the Secretary of Commerce (15 U.S.C. §§330a & 330d ).

harassing golfers in any national park in Washington State or attempting to change the weather without notifying the head of the Commerce Department.

This is not a call for wholesale prosecutions but, rather, for some clear semblance of continuity and consistency in our policies. The case for tougher immigration laws would be stronger if the Trump administration showed the same vigor with regard to both parties to illegal employment. There does seem to be a growing immigration crisis, with sharp increases in unlawful border crossings and the need to reform immigration laws.

However, the dichotomy in enforcement against workers and employers undermines the call to action by President Trump. Most undocumented persons come to the United States for work. Those offering them work are the draw, and sending just three of them to jail is unlikely to change the realities of the market. In the end, widespread of arrests of undocumented persons does little, due to the simple realities of enforcement. We simply cannot jail millions of people or transport them all out of the country.

On the other hand, the number of major employers is far smaller and would be susceptible to deterrent policies of prosecution. It is possible to change the dynamic, but that would mean getting “a little rougher” on the back end of the illegal immigration system. Of course, there is another possibility. While denouncing undocumented workers, Congress and the White House have little interest in removing them from the workforce. We need these workers so, instead, we round up a couple thousand of them in factories and restaurants while effectively ignoring the employers.

The new deal with Mexico, announced late on Friday by President Trump, is an undeniable achievement. It includes a reported agreement to have migrants return to Mexico pending the resolution of their asylum claims. While it is difficult to see how Mexico will humanely house hundreds of thousands of people, the agreement could indeed deter some people from crossing, or at least from surrendering when they reach the United States. For the rest, the calculus of risk remains unchanged, so long as willing employers remain waiting just on the other side of the border.

Jonathan Turley is the Shapiro Professor of Public Interest Law at George Washington University. You can follow him on Twitter @JonathanTurley.