When things are this close and this divided, every vote counts. The latest concern is that people with dimentia and other mental illnesses are voting in significant numbers. From the W Post:
As swing states with large elderly populations such as Florida gear up for another presidential election, a sleeper issue has been gaining attention on medical, legal and political radar screens: Many people with advanced dementia appear to be voting in elections — including through absentee ballot. Although there are no national statistics, two studies in Pennsylvania and Rhode Island found that patients at dementia clinics turned out in higher numbers than the general population.