Originally Posted by RumoredNow
You can not back up and there is no "do over" if you do not submit the form. You end up not being able to vote.
Case in point to suggestion 1.
You can remove a "certain flag thingy" to try again. Of course, for a vote like this a more rigorous way to keep track of who's voted or not than using the same web technology that everyone else uses for unrelated purposes is desired.