Is Illegal Immigration Really a Democratic Plot to Sway Congressional Apportionment?

Illegal immigration has become a defining issue of the 2024 presidential election. Consequently, accusations about our border, immigration process, and immigrants themselves have spread like wildfire across social media and news networks. The latest accusation gaining traction is that Democrats want high levels of illegal immigration because of its effect on the census, congressional apportionment, and electoral college votes. This idea occupied the fringes of the immigration debate until it became a focal point of X CEO, Elon Musk, who has promoted this view on social media. “Most people in America don’t know that the census is based on a simple headcount of people (including illegals) not just citizens." Musk tweeted in February. "This shifts political power and money to states and Congressional districts with the highest number of illegals."

In March, Musk tweeted "Since illegals are mostly in Democrat states, both the House and the Presidential vote are shifted ~5% to the left, which is enough to change the entire balance of power!" In a subsequent X interview with Don Lemon, Musk put a number on that political power alleging that Democrats have gained 20 seats in the House due to illegal immigration.¹ Republican Senator Bill Hagerty of Tennessee said Democrats "want these illegal migrants to create more electoral power for them in their blue states" and estimated Democrats gained 13 seats because of them.

Do these accusations hold up? Does illegal immigration affect the census in such a way that it adds Democratic congressional seats and gives them an electoral college advantage?

In this paper we surveyed the academic research and found that the answer is no. Illegal immigration is responsible for between 0 and 1 additional Democratic representatives in the House based on the 2020 census. 

The Census and the Constitution

The decennial census is enshrined in the Constitution. The original language directed the census to count all people living in the United States, regardless of citizenship status, except for untaxed Native Americans and enslaved people (who counted as three-fifths of a person). In 1790, most Native Americans were considered “not taxed” and were not counted as they were living within America’s borders but in a sovereign nation based on treaties with the United States. The “three fifths of all other persons” represented the counting of slaves as less than a full human being.

After ratification of the Fourteenth Amendment in 1868, apportionment was calculated based upon the “whole number of persons in each State,” thus all African Americans were finally counted in the census as a full person. Throughout the late 19^th century, Native Americans were increasingly counted in the census, but it wasn’t until the passage of the Indian Citizenship Act of 1924 that all Native Americans were guaranteed to be counted in time for the 1940 census.

Over the years, some have advocated for various restrictions, such as “legal voters,” “male citizens,” and “free citizens” to serve as the criteria for inclusion in the census. While proposals to change who is excluded have occurred throughout our history, at no point have they taken effect beyond the initial language in the Constitution. Furthermore, subsequent litigation has been crystal clear on who must be counted in the census -- everyone. In Franklin v. Massachusetts (1992), the Supreme Court ruled that “persons in each State” referred to every individual living in a state on the census date, regardless of their legal status. In Evenwel v. Abbott (2016), the court explicitly stated that apportionment in the House must reflect every member of the community at large. Consequently, when Donald Trump and fellow Republicans tried to exclude undocumented immigrants from the census count, they failed and drew condemnation from the Supreme Court.

The Math: Congressional Seats Impacted by Undocumented Immigrants Do Not Benefit Democrats

While the constitutionality of counting undocumented immigrants in the census is not up for debate, their impact on apportionment is. To answer that question, we relied on the work of five organizations who occupy different spots on the ideological spectrum: The Brookings Institution (center-left), Pew Research Center (apolitical), the Center for Immigration Studies (center-right), the Migration Policy Institute (left), and CATO (libertarian).

According to data from the Brookings Institution, the Center for Immigration Studies (CIS), the Pew Research Center, and Migration Policy Institute (MPI), in 2019 there were anywhere from 10.2 million to 11.4 million undocumented immigrants living in the country.² (We picked 2019 because it is the latest year before the most recent census). Further, this number of undocumented immigrants present is consistent with levels going back to the early 2000s.

What these data show is that the total number of undocumented immigrants has been consistent during both Democratic and Republican presidencies and congresses. In fact, the number of unauthorized immigrants peaked under President George W. Bush in 2007, reaching 12.2 million.

Elon Musk and other prominent Republicans have claimed that undocumented immigrants have given Democrats as many as 20 seats in Congress through apportionment. Let’s start to unpack the math behind apportionment. 

In 1790, the Constitution established 65 seats in the House of Representatives but also granted Congress the ability to increase that number. By 1929, the current number of 435 representatives was established and has remained there ever since.³ What this means is that the population of congressional districts has tripled over the past century from an average of 241,864 after the 1920 census, to 761,952 today. Thus, illegal immigrants do not increase the number of House seats but may change how many there are in each state and how many people inhabit each congressional district. This could, conceivably, affect the partisan makeup of specific seats and Congress as a whole.

As of the most recent census, if we take the approximately 11 million undocumented immigrants present in 2019 and divide by 761,952, that would equal 14 congressional seats and could be where some Republican officeholders get the “13 seats” calculation. The 20 seats cited by Elon Musk is unsupported by any reasonable calculation of the number of undocumented immigrants living in America. But we hasten to add the obvious: this is not 14 additional congressional seats. The number is capped at 435, and illegal immigrants are dispersed to every state in America—blue and red.

The Apportionment Mirage

The leading research on the relationship between illegal immigration and apportionment comes from CIS, MPI, and Pew. Before examining their findings, it is important to note that there is no one database tracking illegal immigration. Studies must rely on data from a combination of sources. Consequently, their findings vary, but only slightly and are illustrative of immigration’s small impact on apportionment.

Let’s begin with the Migration Policy Institute. MPI says Florida is home to 772,000 undocumented immigrants, the equivalent of one congressional seat and one electoral college vote for this red state. New York has 835,000 undocumented immigrants, also one seat and one electoral college vote for this blue state. Texas has 1,735,000 undocumented immigrants, while California has 2,739,000 which would give this blue state an advantage over this red state. But every state has undocumented immigrants: North Carolina (296,000), North Dakota (5,000), Georgia (339,000), and Wyoming (7,000). Apportionment must look at how all the citizen, non-citizen, and undocumented populations work together.

For this take on apportionment, we turn first to the Center for Immigration Studies. CIS began by projecting the population for each state in 2020 and then apportioned House seats using these projections. This data set represented a baseline of apportionment that included all individuals residing in each state. Against this baseline, CIS subtracted its estimate of undocumented immigrants residing in each state. They found that subtracting undocumented immigrants affected the apportionment of six states, either positively or negatively. There was no apportionment effect in the other 44 states.

The blue states of California and New York picked up a congressional seat, as did the red state of Texas. In all likelihood, the two new seats for the blue states sent a Democrat to Congress, and the one new seat in the red state sent a Republican. Likewise, the red states of Alabama and Ohio lost a seat, as did the blue state of Minnesota. All in all, undocumented immigrants likely added one net seat for Democrats, based on the 2020 census, according to CIS. For context, flipping a single congressional seat would not have flipped the power of any recent congressional majority.

Pew Research Center conducted a similar analysis of undocumented populations and their impact on the 2020 census. Pew began by projecting population figures for the 2020 census, which it then used to forecast expected apportionment for each state. Against this baseline, Pew then subtracted unauthorized immigrants.

Pew’s analysis also found that undocumented immigrants affected six states in the 2020 census, with three states gaining a seat and three states losing one. The red states of Florida and Texas picked up a seat, along with blue state California. Red states Alabama and Ohio lost a seat, as well as blue state Minnesota. The net result when broken down along partisan lines—a wash. Democrats and Republicans would have maintained the exact same number of congressional seats; there would be no net difference in representation.

The findings of CIS and Pew are remarkably similar, with the two organizations agreeing on five of the six affected states. The slight difference in their findings is a result of the challenge inherent in measuring the exact number of undocumented immigrants present in the country. Nevertheless, the studies demonstrate that unauthorized immigration’s impact on apportionment is minimal. At most, it accounts for a one seat shift in Congress.

The Electoral College

Electors for the Electoral College are also apportioned using census data. A state’s total number of electors is calculated by adding their total number of House representatives plus two (the number of senators for each state). Given that congressional apportionment and Electoral College apportionment both rely on census data, the partisan impact of undocumented immigration is the same for both–virtually nonexistent. 

While revealing, the data from CIS and Pew reflect undocumented immigration from the 2020 census. We will not know the impact of current levels of undocumented immigration until the next census is taken in 2030. It is impossible to know what the number of undocumented immigrants will be then, but if current trends continue, the Cato Institute found that Republicans might be the ones to benefit during the next population count.

When examining where undocumented immigrants have settled between 2019 and 2023, Cato found that 95% of noncitizen population growth has gone to red states. By far the most popular destination was Texas, but other states leading the charge include Kentucky, South Carolina, and Florida. In concrete terms, over the four-year period, red states gained 1,275,598 noncitizens and blue states gained just 71,973. Should this trend continue, it is likely that Republicans will increase their apportioned seats in Congress and in the Electoral College.

Conclusion

In 2002, John Judis and Ruy Teixeira authored The Emerging Democratic Majority, which argued (among other factors) that the increase of non-white American citizens would give Democrats an enduring electoral advantage into the future. This book was considered a roadmap for some Democrats and may have inadvertently given rise to the far-right conspiracy theory that Democrats are trying to “replace” white people with voters of color. But to be clear, Judis and Teixeira pointed to many other demographic factors that would help Democrats beyond the racial breakdown of the population. They also understood that only legal immigrants had the ability to become citizens and vote in federal elections. And they also recanted and amended their findings as they wrestled with their hypothesis against real world outcomes. 

We have avoided using terms like “replacement theory,” “racism,” and “xenophobia” to describe the views of Elon Musk and others who have been promoting the view that illegal immigration is a deliberate plot to dilute red state power, though we could have. But we are not avoiding the word “wrong.” Their analysis and their conclusions about illegal immigration and apportionment are simply wrong.