Don't trust the Brennan Center, how about the Cato Institute:Every legitimate study ever done on the question shows that voting by noncitizens in state and federal elections is vanishingly rare. That includes the Brennan Center’s own study of 42 jurisdictions in the 2016 general election. We found that election officials in those places, who oversaw the tabulation of 23.5 million votes, referred only an estimated 30 incidents of suspected noncitizen voting for further investigation or prosecution. In other words, even suspected — not proven — noncitizen votes accounted for just 0.0001 percent of the votes cast. But you don’t have to take our word for it: the Cato Institute will also tell you, “Noncitizens don’t illegally vote in detectable numbers.”
Maybe you’re thinking that there are a bunch of noncitizens voting and getting away with it. Again, consider the fact that in order to commit these crimes you create a government record of having committed them. Indeed, anyone can look up your voter history on public voter files. And election officials conduct regular maintenance of these voter lists — in fact, they’re required to by federal law. Moreover, these are crimes that U.S. Citizenship and Immigration Services officers are instructed to look into during the naturalization process. So, if you ever try to become a citizen, you’ll be caught.
Noncitizens Don’t Illegally Vote in Detectable Numbers