And you can not allow everyone who wants to vote vote then sort it out later...What if we find out 2 years after an election that 20K people who arent eligible to vote actually did vote...and that the ineligible voters actually won the election for a candidate. Would two years of legislation, voting records etc have to be changed? What of the other ramifications? Do you leave the person in office that actually lost?
You need to make sure those that are voting meet the states requirements BEFORE the election occurs.