In U.S.elections, when someone shows up at a polling place to cast a vote, but is not on the list of people who may vote there (is not registered in that precinct, or his registation is otherwise invalid or inaccurate), he may be allowed to cast a provisional ballot. The eligibility of the voter is then verified after the election, and, if it is found that he was eligible to vote, his vote is then counted as an ordinary ballot.
A guarantee that a voter could cast a provisional ballot if he believes that he is entitled to vote was one of the guarantees of the Help America Vote Act of 2002.
Provisionalballoting is new to Colorado this year and was instituted to ensure that no eligible voter would be denied the right or ability to vote.
With provisionalballoting, the onus for determining whether or not a voter was eligible to vote rests with the county.
If a provisional voter is found to have cast ballots from a precinct that was not the correct one for his or her address, then election officials must check to see that they voted the right ballots for the precinct that serves their address.
A provisionalballot is counted contingent upon the verification of that voter's eligibility.
Arguments over the use and misuse of the criteria for determining the eligibility of provisionalballots were one of the greatest controversies of the 2004 US Presidential Election - many allege the discrepancies relating to these, particularly in Ohio, may have been a deciding factor in the outcome of the election.
A guarantee that a voter could cast a provisionalballot if he or she believes that they are entitled to vote was one of the guarantees of the Help America Vote Act of 2002.