These Are the Political Consequences of Excluding Undocumented Immigrants from Apportionment

Angela X. Ocampo
Published in
6 min readAug 14, 2020


Written by Jonathan Robert Cervas and Angela X. Ocampo

Last month, the Trump administration issued a memorandum directing the U.S. Secretary of Commerce to exclude all undocumented immigrants¹ residing in the U.S. from the Census apportionment base. Every ten years, a re-numeration of the population, carried out by the Census, is necessary because of population shifts. Using the Census enumeration, as required by the Constitution to ensure ‘one person, one vote’, the 435 members of the U.S. House of Representatives are redistributed accordingly.

If Trump’s memorandum were to go into effect, this would require an adjustment of the population base, resulting in some states gaining representation, while others losing. We conducted a hypothetical re-apportionment to find out the potential impact of Trump’s memorandum.

Source: Jonathan Robert Cervas

The Constitution versus Trump

The U.S. Constitution, as drafted in 1789, requires that Representatives “be apportioned among the several states…” After the ratification of the fourteenth amendment in 1868, the constitution states that “Representatives shall be apportioned among the several states according to their respective numbers, counting the whole number of persons in each state, excluding Indians not taxed.”

President Trump’s memo states that, as president, Congress has delegated him the right to determine if the Census enumeration is correct before he delivers it to Congress (13 U.S.C. 141(b)). Further, according to Trump, it is “the President’s personal transmittal of the report to Congress” that “settles the apportionment.” The memorandum argues that the Constitution is not explicit about who is to be included as a “persons in each state.” At various times, Trump argues, this has been interpreted to include only those who are regular inhabitants of a state. He, therefore, concludes that as president he has been delegated the discretion to determine who is an inhabitant of a state. Using this authority, he has ordered that undocumented immigrants be excluded from the apportionment base; this is an unprecedented move as apportionment has always used total population counts.

Trump’s Persistent anti-immigrant agenda

This recent memorandum comes just weeks after the Supreme Court decided against the administration’s plan to rescind the DACA program. DACA, a program instituted under President Obama, provides undocumented people brought to the U.S. as children who meet certain requirements with work permits and a reprieve from deportation. Trump’s memo also builds off earlier attempts by his administration to implement drastic changes to the U.S. Census. Back in March of 2018, Secretary of Commerce Wilbur Ross indicated his intention to add a citizenship question to the 2020 Census.

This decision triggered a legal battle between the Trump administration and dozens of states, cities, and organizations that filed lawsuits against this decision. Both U.S. Census and academic experts warned against the detrimental impacts of adding a citizenship question to the Census, citing the potential population under-counts that it could result in among both documented and non-documented immigrants. The Supreme Court ruled that a citizenship question could not be added to the 2020 U.S. Census because the justification that the government offered at the time for including the question was just a pretext (Department of Commerce v. New York, №18–966, 588 U.S. ___)

Here is how we did our research

Although the constitutionality, legality, and feasibility of Trumps’ memo remain unclear, excluding undocumented immigrants from the population base for re-apportionment is certain to bring significant representation changes.

In order to assess the potential consequences of Trumps’ order, we conducted several hypothetical re-apportionment analyses. First, we used the most recent data released from the American Community Survey (ACS 1-year ‘16,’17,’18) to project population growth between 2018–2020.

We use the 2018 1-year ACS population as the base population, and then add to that a percent in each state equal to the change over the 2016–2018 period. This base allows us to calculate estimated apportionment for 2020. Final population totals delivered by the President to Congress will determine the exact number of representatives each state will receive. While most states, as usual, are not affected by apportionment changes, our results show that seven states are expected to gain representation while nine states are expected to decrease their representatives based on expected population shifts alone.

Source: Compiled by the authors. Asterisk (*) Indicates estimated change if Trump’s order were to take effect. Final numbers subject to change based on actual Census enumeration. Undocumented estimates come from Migration Policy Institute. States not show won’t have any estimated changes. [Full analysis shown here]

The ACS data used to calculate apportionment above includes undocumented immigrants, and therefore would need to be corrected to estimate the effect of Trump’s order. We rely on data from the Migration Policy Institute to estimate the undocumented population in each state. Although these numbers are the best publicly available data, they are estimates, which may have also changed since 2017, the year they were published. There may have been population shifts since 2016 that will be uniquely captured in the 2020 Census. Therefore, this analysis should be interpreted considering these limitations.

According to the MPI data, 11,300,000 unauthorized immigrants live in the U.S. as of 2016. The largest proportion of undocumented immigrants is in California with over three million. Our results indicate that California would lose one additional seat under Trumps’ new order when compared to the seats it would lose to population shifts alone.

Instead of gaining 3 seats because of its population growth, Texas would instead gain only one; New Jersey, which would not ordinarily lose any seats due to population shifts, would lose one. Michigan and Ohio both retain the seat they would have lost if Trump is successful. Alabama, which is expected to lose one seat, would retain its seat if undocumented immigrants are excluded from the population base. A pending court challenge against the Dept. of Commerce from Alabama contends the constitution requires the same change found in Trump’s memo (Alabama v. U.S. Dept. of Commerce, Case No.: 2:18-cv-00772-RDP).

Source: Compiled by the authors. Map shows the distribution of non-naturalized, foreign born population in Congressional Districts. Some of these people would not be excluded from apportionment given Trump’s order, but the lack of precise data on undocumented people makes locating and estimating this population nearly impossible. Data is generated from American Community Survey 1-year data and Congressional Districts are current for 2020. [Full Size]

The upshot

If the Trump administration succeeds in excluding undocumented immigrants from the population base count for re-apportionment this would mean a significant shift away from representation in highly diverse, mostly urban areas and into lower-dense, mostly white areas.² Although, we have estimated some of the effects of Trumps’ memo, there are additional consequences that are likely to emerge.

The anti-immigrant agenda that has characterized the Trump administration from day one is likely to continue into the 2020 Presidential Election. Moreover, the President’s memo will likely ignite the battle over what constitutes the proper population base for apportionment. In Evenwel v. Abbott (578 U.S. __, 2016), the Supreme Court rejected the argument that the state of Texas was constitutionally required to draw districts with equal numbers of eligible voters.

It, however, was silent about whether a different population base could be used for redistricting in the future. The President’s persistent anti-immigrant agenda will continue to shape politics in the foreseeable future.

Author Biographies

Jonathan Robert Cervas is a Post-doctoral Fellow at Carnegie Mellon University in the Institute for Politics and Strategy. His research is focused on American political institutions. He has published on both elections and gerrymandering, and has worked on three federal redistricting court cases involving minority rights.

Angela X. Ocampo is Assistant Professor of Political Science at the University of Michigan. Her research is focused on political behavior, representation, race, ethnicity and politics and Latina/o/x politics.


¹ Despite the usage of the terms ‘illegal aliens’ in both the memorandum and other federal government communication, we instead refer to this population as undocumented.

² Concurrent with the writing of this piece and our own analysis, Pew Research Center’s re-apportionment analysis has found results consistent with ours.



Angela X. Ocampo

Assistant Professor of Political Science at the University of Michigan.