Earlier quoted context omitted.
They literally just charged someone in Philadelphia for illegally voting in every federal election since 2008. Non-citizen, ordered deported back in 2000 but still in the country. There's not been a reliable audit to show the extent to which this happens (probably not enough to affect even local elections), but to say that it isn't happening is just a lie.
If you listen carefully to the "ballot access" side of this argument (actually informed people and politicians, not random on the internet), you will see they don't ever say it does not happen. What they say is that it does not happen enough to plausibly come close to affecting the outcome. And this is widely supported, including by right-wing organizations (as a sibling comment observes). As with most issues, there…
> Source: actually ran a fucking election precinct. Non-citizens aren’t casting ballots illegally.
So, you can see people are actually claiming that it doesn't happen. Further,
> It's already a crime, and we seem to be pretty good at catching it.
How can we be good at catching it if it is too hard for our own citizens to actually get proof that they are citizens? We hear about the cases that happen, but we don't hear about the people go go undetected, because they go undetected.