It’s become clear over the last few months that something very funny is going on with immigration enforcement statistics (here, here, and here). The data generally show that interior enforcement, what most people commonly think of as “deportations” (but also includes I‑9, Secure Communities, and E‑Verify), has declined as a percentage of total removals. Many of the removals appear to be unlawful immigrants apprehended by Customs and Border Protection (CBP) and then turned over to Immigration and Customs Enforcement (ICE) for removal – a trend that began in 2012 and accelerated in 2013. That transfer makes it appear as if there was more internal enforcement than there really was. The administration is therefore deporting an increasing number of recent border crossers and a decreasing number of unlawful immigrants apprehended in the interior.


It appears, then, that President Obama’s reputation for severe interior enforcement was earned for 2009, 2010, and 2011 but is somewhat unjustified in 2012 and 2013. The Bipartisan Policy Center has an excellent report on the enormous court backlogs and other issues that have arisen due to interior immigration enforcement. I’m waiting for additional information from a FOIA request before wading into the data surrounding the interior versus border removals controversy because we do not have data on internal enforcement numbers prior to 2008.


Interior enforcement is only part of the government’s immigration enforcement strategy and must also be looked at as a component of broader immigration enforcement that includes border enforcement.

Jessica Vaughan at the Center for Immigration Studies (CIS) combines returns at the border and removals that appears to show President Obama as the weakest immigration enforcer in decades. Her conclusion mistakenly conflates lower numbers of unauthorized immigrant crossers with a lack of enforcement. Since fewer unauthorized immigrants are crossing the border now than prior to the Great Recession, the decrease in returns is due to the decreasing quantity of crossers and not a lack of enforcement. However, Vaughan’s combination of border enforcement’s returns of unlawful immigrants and interior enforcement’s deportation numbers rightly shows how linked these two functions of immigration enforcement are.


After reading research from CIS for years, I can safely assume that they view border and interior immigration enforcement as complementary. Increased border enforcement multiplies the effectiveness of interior enforcement and vice versa. Under their view, less interior enforcement will lead to less effective immigration enforcement even if all of those resources are transferred to border enforcement – losing out on the supposed synergies that only exist when both types of enforcement work in tandem. Unsurprisingly, I think interior and border enforcement are more likely to be substitutes than complements – but imperfect substitutes. Moreover, many more resources would have to be devoted to interior enforcement to get the same deterrent effect from an equivalent amount of resources devoted toward border enforcement.


Some history of immigration enforcement strategy: Since the mid‐​1990s, the border enforcement strategy has been one of “prevention through deterrence” – the idea that concentrating personnel, infrastructure, and surveillance along the most crossed regions of the border will most effectively discourage unlawful immigration. By reducing the flow, the long run gradual attrition and voluntary return migration will gradually reduce the stock of unauthorized immigrants.


According to the Congressional Research Service,

[s]ince 2005, CBP has attempted to discourage repeat entries and disrupt migrant smuggling networks by imposing tougher penalties against certain unauthorized aliens, a set of policies eventually described as “enforcement with consequences.” Most people apprehended at the Southwest border are now subject to “high consequence” enforcement outcomes. Across a variety of indicators, the United States has substantially expanded border enforcement resources over the last three decades. Particularly since 2001, such increases include border security appropriations, personnel, fencing and infrastructure, and surveillance technology.

The strategic goals of interior enforcement are similar to the goals of border enforcement. According to Bryan Roberts, Ted Alden, and John Whitley at the Council on Foreign Relations, the goals of interior enforcement are to “turn off the jobs magnet” and prompt “attrition through enforcement” (pp. 34–35). In other words, the strategic goal of interior immigration enforcement is to deter the entry of unauthorized immigration and then incentivize the return of those who come anyway.


This leads us to the issue of whether interior enforcement is even effective.


Assuming that the effectiveness of immigration enforcement should be maximized, shifting immigration enforcement actions from interior to border enforcement makes more sense. Bryan Roberts, Ted Alden, and John Whitley sum up the studies and evidence comparing the marginal effectiveness of additional resources spent on border versus interior enforcement (pp. 34–38). For both categories, the main effect is to change immigrant behavior once in the United States or to change their mode of entry. The decision to unlawfully enter is not reconsidered due to increased internal enforcement. The exceptions are two studies that purported to find that increased interior enforcement was twice as cost effective as border enforcement in Arizona, mainly by lowering the wage for unauthorized immigrants. Those studies were written before it was revealed how ineffective E‑Verify has been in lowering wages for unauthorized immigrants in Arizona (the results might be different if E‑Verify was nationalized), so the deterrent effect is likely less than reported.


The counter argument to the common finding that interior enforcement is inefficient is that it has not really been tried, so we don’t necessarily know how effective it could be if more resources were devoted to it. Given the disappointing (from the restrictionist point of view) results of E‑Verify, the lack of studies investigating the deterrent effect of Secure Communities, and the known effectiveness of border enforcement in deterring unlawful entries, shifting resources from internal enforcement to border enforcement is likely a better use of scarce resources to disincentivize unauthorized immigration.


Border enforcement is likely getting more effective. A December 2012 GAO report found that about 81 percent of all those who attempted to enter illegally along the Southwest border in 2011 were either apprehended or turned back (caution, the denominator is not always known here). That percentage is up dramatically from previous years.

Get Aways, Apprehensions, and Turnbacks on the South West Border

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Source: GAO.



Apprehensions and Turnbacks as a Percent of Estimated Unlawful Entries


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Source: GAO.

The government has been getting better at border security although the decrease in the number of unauthorized border crossers due to the poor economy can take most of the credit. The reallocation of interior immigration enforcement resources to border enforcement appears to be rational from the perspective of a government seeking to increase the deterrent effect of immigration enforcement. Effective border security likely affects the flow of unauthorized immigrants more directly than the stock, but it also leads to long run decreases in the latter. 


None of this blog post should be taken as an endorsement of a heavy‐​handed enforcement‐​only strategy to diminish unauthorized immigration. The best way to have well‐​enforced immigration laws is to have better laws that allow lower skilled immigrants to come permanently or temporarily to work with minimal regulations. Channeling lower skilled workers into the legal market will dramatically reduce the flow of unlawful immigrants, making immigration enforcement along the border more effective – similar to how current border enforcement is more effective during the lousy economy, but without having to suffer low economic growth. Visa overstays are another matter entirely.


A decrease in interior immigration enforcement relative to increased border enforcement does not signal the end of immigration enforcement, as so many are hyperbolically claiming. Interior and border immigration enforcement are substitutes, but border enforcement is much more efficient at actually deterring unauthorized immigration – the actual strategic goal of immigration enforcement.