Good public policy recognizes that people respond to incentives. In the case of the Southern border, inadmissible migrants will continue trying to cross as long as they believe the benefits of an attempt outweigh the costs. Of course, part of the migrant’s cost-benefit analysis is beyond the influence of U.S. policy. There is generally little the U.S. can do to end the episodes of recession, instability, or lawlessness in foreign countries that may push residents into leaving. Where border policy can affect the migration calculus is in the probability of success and the consequences of failure. If inadmissible migrants come to believe they are unlikely to gain entry, either at or between ports of entry, and that they will face significant penalties if they attempt to enter without inspection, then illegal immigration will decline.
Just as the careless driver who leaves his car unlocked incentivizes auto theft, our lax border policy incentivizes illegal immigration.
A clear example of changing the probability of success occurred in 2019. As the border became inundated with migrants claiming asylum in order to gain immediate entry, the Trump administration began requiring asylum seekers to remain in Mexico while their cases were adjudicated. Because most of these asylum seekers were actually economic migrants who would not ultimately win their cases, eliminating the possibility of immediate entry reduced their incentive to make claims. DHS subsequently observed “a rapid and substantial decline in apprehensions in those areas where the most amenable aliens have been processed and returned to Mexico”.
When President Biden moved to abandon the Remain in Mexico policy upon taking office, he helped spark new migrant waves. The administration’s policies have been “akin to posting a flashing ‘Come In, We’re Open’" sign on the southern border, as one federal judge put it, and this week’s executive order on the border will do little to change that.
Nevertheless, immigration advocates tend to downplay the role of U.S. policy in incentivizing migration. For example, at a recent Center for Migration Studies event, Donald Kerwin rejected alternative explanations for the border surge and instead cited the difficult situations in sending countries:
I think the list of the top 10 [recent sending] countries tells its own story. You have Venezuela's economic collapse and criminality, Nicaragua's descent into authoritarianism, Haiti really a failed state whose prime minister is in hiding and just resigned, Ecuador becoming a major drug hub, Peru with its political unrest and highest fatality rate in the world from Covid, climate displacement in Guatemala and the like.
Outside events do help motivate particular migrant groups, but that doesn’t mean border enforcement is ineffective or irrelevant. By way of analogy, imagine a city driver who parks his car with the windows open and the keys on the dashboard. After his car is stolen, he could blame the theft on failing schools, industrial decline, and skill-biased technological change — but none of these “root causes” alters the fact that he would probably still have his car had he closed and locked it. Just as the careless driver incentivizes auto theft, our lax border policy incentivizes illegal immigration.
The claim that enforcement is ineffective as a deterrent sometimes finds its way into academic journals, but the supporting evidence is weak. For example, a 2018 study in Latin American Research Review uses survey data to show that Central Americans who are more aware that the U.S. has increased border enforcement are no less likely to consider migrating. If border enforcement does not affect the migration decision, the authors reason, then there must be no deterrence. This conclusion has two problems. First, although knowledge of enforcement measures may deter some migrants, the Central Americans who want to migrate are the most likely to research those measures in the first place, leaving the expected relationship between enforcement knowledge and intent-to-migrate ambiguous. Second, a deterrence policy will work only to the extent that it actually does raise the costs and lower the benefits of migrating. Empty gestures — e.g., “drones on the border” — will show equally empty results.
A more informative study of the impact of border enforcement appeared in the American Economic Journal in 2021. The authors found that apprehended migrants who are eligible for “sanctions” — which could include restrictions on future visa eligibility, relocation far from the point of apprehension, and criminal prosecution — are much less likely to be re-apprehended, which implies they make fewer attempts. The analysis is based on actual apprehension data — not surveys where potential migrants merely speculate about how enforcement may affect their decisions. The results show that enforcement can indeed alter the incentive structure in ways that discourage migration.
Steps to discourage illegal immigration need not stop at the border. Enforcing laws against hiring unauthorized workers can also change the cost-benefit calculus for potential migrants. The most effective worksite tool is E-Verify, which employers can use to check whether their employees are authorized to work in the U.S. A study published in the academic journal Policy Studies in 2021 found that mandatory E-Verify stood out during the 2005-2010 period of analysis as the policy most strongly associated with lower numbers of illegal immigrants within a state. One need not rely entirely on econometrics to assess E-Verify, however, because intense opposition from employers of illegal labor is its own kind of evidence. These employers are not nearly so exercised about drones on the border!
Policymakers could go much further to disincentivize illegal immigration by mandating nationwide E-Verify, restoring Remain in Mexico, tightening asylum eligibility rules, ending catch and release, and restricting parole. The policy levers are available, but, as of this moment, the political will is not.