Do non-citizens vote in U.S. elections?

Source: Do non-citizens vote in U.S. elections?


  • First use of representative sample to measure non-citizen voting in USA.
  • Some non-citizens cast votes in U.S. elections despite legal bans.
  • Non-citizens favor Democratic candidates over Republican candidates.
  • Non-citizen voting likely changed 2008 outcomes including Electoral College votes and the composition of Congress.
  • Voter photo-identification rules have limited effect on non-citizen participation.


Four design characteristics make this survey uniquely valuable for our purposes. 1. It has an enormous sample size, which makes feasible sub-population analyses (n = 32,800 in 2008 and n = 55,400 in 2010). 2. It included a question about citizenship status. 3. Many non-citizens were asked if they voted, unlike other large surveys which filter out non-citizens before asking about voting. 4. Participation and registration were verified for at least some residents in nearly every state for the 2008 survey (Virginia state law barred voting verification).

Inclusion of a validated voting measure is particularly valuable in this context because of important and contradictory social and legal incentives for reporting non-citizen electoral participation. Although variation in the social desirability of voting may skew estimates (Ansolabehere and Hersh, 2012) as for other populations, legal concerns may lead some non-citizens to deny that they are registered and/or have voted when in fact they have done both. Validation of registration and voting was performed by the CCES research team in collaboration with the firm Catalyst. Of 339 non-citizens identified in the 2008 survey, Catalyst matched 140 to a commercial (e.g. credit card) and/or voter database. The vote validation procedures are described in detail by Ansolabehere and Hersh (2012). The verification effort means that for a bit more than 40 percent of the 2008 sample, we are able to verify whether non-citizens voted when they said they did, or didn’t vote when they said they didn’t. For the remaining non-citizens, we have only the respondent’s word to go on concerning electoral participation, although we do attempt to make inferences about their true participation rate based upon the verified portion of the sample.


3.1. Registration

Non-citizen voter registration is a violation of election law in almost all U.S. jurisdictions, the lone exceptions are for residents of a few localities in Maryland. Most non-citizens did not cross the initial threshold of voter registration, but some did. In 2008, 67 non-citizens (19.8%) either claimed they were registered, had their registration status verified, or both. Among the 337 immigrant non-citizens who responded to the CCES, 50 (14.8%) indicated in the survey that they were registered. An additional 17 non-citizens had their voter registration status verified through record matches even though they claimed not to be registered. Perhaps the legal risks of non-citizen registration led some of these individuals to claim not to be registered. In 2010 76 (15.6%) of non-citizens indicated that they were registered to vote in either the pre-election or post-election survey waves.

In 2008, the proportion of non-citizens who were in fact registered to vote was somewhere between 19.8% (all who reported or had verified registration, or both) and 3.3% (11 non-citizen respondents were almost certainly registered to vote because they both stated that they were registered and had their registration status verified). Even the low-end estimate suggests a fairly substantial population of registered-to-vote non-citizens nationwide. Out of roughly 19.4 million adult non-citizens in the United States, this would represent a population of roughly 620,000 registered non-citizens4. By way of comparison, there are roughly 725,000 individuals in the average Congressional district.

The “adjusted estimate” row presents our best guess at the true percentage of non-citizens registered. It uses the 94 (weighted) non-citizens from 2008 for whom Catalyst obtained a match to commercial and/or voter databases to estimate the portion of non-citizens who either claim to be registered when they are not (35%) or claim not to be registered when they are (18%). We then use these numbers to extrapolate for the entire sample of non-citizens in 2008 and 2010. Because most non-citizens who said they were registered were in fact registered, and quite a few who said they were not were actually registered, the adjusted estimate is the highest of the three estimates, indicating that roughly one quarter of non-citizens were likely registered to vote (Table 1).


How many non-citizen votes were likely cast in 2008? Taking the most conservative estimate – those who both said they voted and cast a verified vote – yields a confidence interval based on sampling error between 0.2% and 2.8% for the portion of non-citizens participating in elections. Taking the least conservative measure – at least one indicator showed that the respondent voted – yields an estimate that between 7.9% and 14.7% percent of non-citizens voted in 2008. Since the adult non-citizen population of the United States was roughly 19.4 million (CPS, 2011), the number of non-citizen voters (including both uncertainty based on normally distributed sampling error, and the various combinations of verified and reported voting) could range from just over 38,000 at the very minimum to nearly 2.8 million at the maximum.