One early success of President Trump’s promised hard line against illegal immigration is the decline in border apprehensions. This decline is being touted by the administration and credited by the media as evidence that a tough policy can be successful in deterring illegal immigration.

The current issue of the Atlantic monthly cites, “How Trump Is Upending the Conventional Wisdom on Illegal Immigration.” In support of its analysis, it cites “The Department of Homeland Security reports that illegal crossings across the southern border plunged 40 percent in the first month of the Trump presidency, the steepest decline in illegal migration since the recession of 2009.”

This commentary is logical, but it also can be misleading. A glance at the history of enforcement efforts against illegal border crossing offers a cautionary lesson. Passage of the Immigration Reform and Control Act in 1986 made it illegal for the first time for an employer to knowingly hire an illegal alien. This law served notice on employers that they no longer would be able to hire and exploit illegal workers. By thus denying jobs to illegal workers this law was supposed to deter them from coming into the country looking for work. That measure was also the justification for adopting an amnesty for those already illegally in the country.

The results – as measured by the apprehension of illegal aliens at the border – indicated that the measure was a success. That is, it was a success for about the first two following years. But, after that short hiatus, the flow of illegal immigration – again measured by border apprehensions – zoomed. What happened was that both employers and prospective illegal workers soon learned that the new law was toothless because counterfeit work documents took the employer off the hook of responsibility for knowingly hiring illegal workers.

The moral is that, if there is not follow up action by the administration in effectively enforcing laws against illegal immigration, a similar resurgence in illegal immigration is possible. If that were to occur, the administration’s pledge to combat illegal immigration would prove to be fangless.