Subfederal Immigration Regulation and the Trump Effect

46 Pages Posted: 15 May 2018 Last revised: 20 Aug 2018

See all articles by Huyen Pham

Huyen Pham

Texas A&M University School of Law

Van H. Pham

Baylor University - Department of Economics

Date Written: May 1, 2018


The restrictive changes made by the Trump presidency on U.S. immigration policy have been widely reported: the significant increases in both interior and border enforcement, the travel ban prohibiting immigration from majority-Muslim countries, and the termination of the DACA program. Beyond the traditional levers of federal immigration control, this administration has also moved aggressively to harness the enforcement power of local and state police to increase interior immigration enforcement. To that end, the administration has employed both voluntary measures (like signing 287(g) agreements deputizing local police to enforce immigration laws) and involuntary measures (threatening to defund jurisdictions with so-called “sanctuary” laws). What has been the Trump Effect on subfederal governments’ immigration policies? Have they fallen in line with the federal push for restrictive policies and increased enforcement or have they resisted? Using our unique Immigration Climate Index (ICI), we track the response of cities, counties, and states by analyzing the immigration-related laws they enacted in 2017, the first year of the Trump administration, and compare it to previous years’ activity. Based on our data, we make several observations. First, subfederal governments have responded with surprising speed and in unprecedented numbers to enact laws that are almost uniformly pro-immigrant. In response to increased federal enforcement, these subfederal governments have enacted “sanctuary” laws limiting their cooperation with federal immigration enforcement. Most of these laws were enacted by cities and counties, which enacted more immigration regulations in this one year than they enacted during the previous 12 years added together (2005-2016). Second, in the context of historical ICI scores, these immigrant-protective laws help to pull the national ICI score sharply upward. By assigning scores (positive or negative) to each subfederal immigration law, our ICI has tracked the climate for immigrants on a state-by-state basis and identified distinct phases in subfederal immigration regulation since 2005. Though the national ICI score (where individual state scores are added together, through time) remains highly negative, we observe a distinct Trump effect in 2017: the immigrant-protective laws enacted by certain jurisdictions are creating more positive climates for immigrants in those jurisdictions. Finally, the nature of governmental sanctuary in 2017 is distinctly more diverse than the sanctuary we have seen in decades past. In 2017, the most active sanctuary cities are not the big urban cities we saw in past years, but rather, are medium-sized cities and suburbs with populations between 50,000-100,000 people. Though most of these smaller jurisdictions voted for Hillary Clinton in the 2016 presidential election, a surprising number voted for Trump. Moreover, we also see the emergence of new sanctuary entities — public school districts, public universities, and even mass transit authorities — which have limited their own cooperation with federal immigration enforcement. This diversity in government sanctuary reflects another aspect of the Trump Effect: how harsh immigration enforcement policies under this administration have made immigration issues much more important to a wider range of communities and to a larger range of policy areas.

Keywords: Immigration, Immigration Enforcement, Subfederal, State Government, Local Government, City, County, Federalism, Trump, Police, Police Enforcement, Sanctuary City, Sanctuary Cities

JEL Classification: K37, K14, K42

Suggested Citation

Pham, Huyen and Pham, Van H., Subfederal Immigration Regulation and the Trump Effect (May 1, 2018). New York University Law Review, 2019, Texas A&M University School of Law Legal Studies Research Paper No. 18-22, Available at SSRN:

Huyen Pham (Contact Author)

Texas A&M University School of Law ( email )

1515 Commerce Street
Fort Worth, TX Tarrant County 76102
United States


Van H. Pham

Baylor University - Department of Economics ( email )

One Bear Place #98003
Waco, TX 76798
United States
(254) 710-3521 (Phone)
(254) 710-6142 (Fax)


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