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U.S.-Mexico Apprehensions Drop, But Causes Remain Elusive

Over the last year, the arrival of large numbers of Central American families and children at the U.S.-Mexico border led to a sustained growth in apprehension numbers. However, the newest Department of Homeland Security Southwest border apprehension data1 show that apprehensions dropped in June 2019, marking the first major reversal in these figures since the start of the Central American migration crisis in early 2018. Although the White House and immigrant advocates have debated whether increased enforcement or seasonal temperatures caused this decline, it is too early to assign any one factor as responsible for these numbers without reviewing additional data from the rest of the fiscal year.

Overall, Customs and Border Protection (CBP) recorded 94,987 total apprehensions at the U.S.-Mexico border in June 2019. While this number represents a 28.5 percent drop from 132,880 in May, it remains consistent with recent levels over the last year. As Figure 1 shows, this decline falls in line with patterns seen between October 1999 and October 2009 when numbers would spike in May before declining through the rest of the calendar year. Given that the period between October 1999 and October 2009 involved apprehensions of single Mexican men, these parallels may emerge from different underlying demographic, economic, and political factors.

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Figure 1: Monthly Southwest Border Apprehensions (FY2000-FY2019)

Source: CBP

June also saw a decrease from May 2019 in the number of apprehensions across the three categories of migrants tracked by CBP. For instance, family unit apprehensions dropped from a record high of 84,491 in May to 57,389 in June, single adult apprehensions declined from 36,900 to 30,130, and unaccompanied children apprehensions decreased from a record high of 11,489 to 7,378 in the one month period.

Figure 2: Categories of Southwest Border Apprehensions (FY2012-FY2019)

Source: CBP (1)(2)

Finally, CBP has recorded 688,375 apprehensions so far for fiscal year (FY) 2019, which surpasses the total yearly number for every year between FY2009 and FY2018. Despite the decline in apprehension levels in June, FY2019 still is on track by October to have more apprehensions than FY2009.

Figure 3: Yearly Southwest Border Apprehensions (FY1980-FY2019)

Source: CBP (1)(2)

The reasons for the recent drop in apprehensions have been the subject of debate. After President Trump threatened to hit Mexican goods with increasing tariffs unless Mexican President Andrés Manuel López Obrador clamped down on Central American migrants, Mexico’s efforts to meet these obligations over the last two months led to Mexico detaining and deporting more migrants. However, Figure 1 shows that Southwest border apprehensions usually decline around this time of year as summer temperatures make the journey through Mexico and across the border more dangerous for migrants, a trend that persists even as these seasonal changes have been less drastic in recent years. Additionally, migrants and smugglers may be waiting to see if Mexico will wind down its enforcement push before taking the journey.

While all three of these factors likely played a role in generating June’s decline in apprehension numbers, stakeholders in the immigration debate tend to choose ones that support their narrative. The Trump administration touted Mexico’s enforcement efforts as the main reason these numbers dropped, attempting to justify Trump’s tariff gambit with Mexico. In contrast, immigration advocates have been arguing that these numbers merely mark seasonal reductions to counter the administration’s narrative that enforcement played a role here. However, one month of data is insufficient to determine whether this trend will reverse or continue through the end of the fiscal year, making it prudent to wait before attempting to pin a definitive explanation to this latest development.

1 This blog post examines the number of migrants that CBP apprehended between ports of entry along the U.S.-Mexico border. It does not include the number of individuals that CBP recorded as inadmissible at ports of entry at this border.