During the 2024 presidential race, former President Donald Trump and his allies, including X owner Elon Musk, have promoted an unfounded conspiracy theory that undocumented migrants are being allowed into the U.S. to vote.

Trump’s false claims of widespread voter fraud by undocumented immigrants are not new. In 2020, after losing his reelection bid, he alleged that tens of thousands of noncitizens voted in the battleground state of Arizona, which election officials there disputed. Trump made similar claims about illegal voting as far back as 2014.

Voter fraud by noncitizens — including both lawful immigrant residents and those here illegally — is very rare, experts have found, and studies have found no evidence of widespread noncitizen voting in previous elections. Ahead of the 2024 general election, here are key facts to know.

Undocumented immigrant voting is rare

Multiple studies and investigations have concluded there have been very few instances of noncitizens voting in federal elections in modern history.

After the 2016 election, analysis by the nonpartisan Brennan Center for Justice found 30 cases of suspected noncitizens voting reported by election officials out of 23.5 million votes cast in the 42 jurisdictions reviewed. 

A Washington Post analysis of the conservative Heritage Foundation’s database of voter fraud cases brought by prosecutors found just 85 cases involving allegations of noncitizen voting over a two-decade period from 2002 to 2023.

The data indicates noncitizen voting is not going to sway the election outcome this November, according to Alice Clapman, senior counsel for voting rights at the Brennan Center.  

“You look at the margin between candidates in a presidential election, and it is vastly more than even the most inflated figure of the handful of noncitizens who have been found to have voted,” Clapman said. 

There are severe penalties for noncitizens who try to vote illegally 

It is illegal for noncitizens to vote in federal elections. Violators risk not only deportation, but fines and up to one year in federal prison. Additionally, falsely claiming U.S. citizenship while registering to vote can result in imprisonment for up to five years.

If noncitizens commit voter fraud, they create government records of their actions — meaning it’s possible for them to be caught.

U.S. Citizenship and Immigration Services officers are told to check public voter files during the naturalization process to see if applicants have attempted to vote, according to the Brennan Center. 

“If somebody is undocumented, they want nothing to do with anything that would bring them to the attention of authorities, or jeopardize their status if they have temporary status,” Clapman said.

People must attest that they are U.S. citizens when registering to vote

When registering to vote, individuals must attest to their U.S. citizenship under penalty of perjury on the federal voter registration form.

The form does not require documentation or proof of citizenship, but federal law requires voters to provide a driver’s license number or the last four digits of their Social Security number at minimum to register in every state. 

Some noncitizens authorized to work in the United States by the Department of Homeland Security can have a Social Security number, according to the federal agency, and unauthorized immigrants can get driver’s licenses in 19 states.

But states cross-check information of voter registration applicants with state and federal databases to keep noncitizens off voter rolls, according to David Becker, executive director of the Center of Election Innovation and Research and CBS News’ election law contributor.

“If you have a driver’s license number and it turns out you’ve got a green card, the DMV has that,” Becker said. “Are there instances when people fall through the cracks? Yes. But this is why when Republican states try to look for noncitizens voting, they find incredibly low numbers.”

Ineligible voters are regularly removed from state voter rolls 

The federal government has required states to regularly maintain voter rolls since the passage of the National Voter Registration Act in 1993. This maintenance process removes ineligible voters, often those who have died or moved.

States also attempt to flag noncitizens who may have been added to voter rolls in error. As part of this process, some states verify citizenship by cross-checking voter information with databases like the federal SAVE program, which can confirm U.S. citizenship. 

It takes years for immigrants to become naturalized citizens

Trump and Musk have repeatedly implied that migrants entering the U.S. under the Biden administration can quickly gain voting eligibility in time for the 2024 election, but this is misleading.

By federal law, a noncitizen must live in the United States for at least 5 years — or 3 years if you are married to a U.S. citizen — as a legal permanent resident (green card holder) before they can apply for citizenship. 

Applicants must meet certain eligibility requirements to receive a green card in the first place, and the vast majority of applicants never receive one, according to analysis of federal data by the Cato Institute, a conservative think tank.

In recent years, the Biden-Harris administration has implemented more restrictive asylum rules that have made it even more difficult for migrants to pursue asylum and an eventual path to citizenship.