There is nothing stopping illegals, non-citizens, felons, or other prohibited persons from registering to vote and then voting.
Did you have to show your birth certificate, naturalization papers, or criminal background check when you registered? I didn't. All I needed was an ID.
While it is illegal for prohibited people to vote, it's only if they get caught. There is no machine in place to flag them at the registration or ballot-casting process.
Illegals cannot legally get drivers licenses in most states, which are generally used as IDs.
The 12 states which allow illegals to get drivers licenses are thus tacitly or opening allowing illegals to vote. In OR and CA and maybe other states, those getting DL are automatically registered to vote, which is another pile of crap.
It seems that in order to register to vote, one should have to prove citizenship, and I hope that changes.
Unless, of course, ICE sets up covert cameras and runs DHS’s facial recognition suite using their combined databases.