I live in Mexico, as an American expat. Your national ID with picture is require to vote. The voter log at the poll has your picture. You leave your thumb print when voting and your index finger is put in purple ink to prevent you from voting twice.
Geez, even a third world country like Mexico has tighter voter security than we do... Pathetic...
Here in Oklahoma, you have to have a DL or photo ID, and they like you to have your voter registration card, and you sign the log book, but that is it...