In a very close race, voter ID measures could affect the outcome. In the extreme scenario, it could flip the Presidential election. How?
About 10% of Americans currently lack government-issued ID. This is a Democratic-leaning population. The percentage is higher among African-Americans. States that have new voter requirements include Pennsylvania, Florida, Iowa, Virginia and Ohio. This is disconcerting considering the fact that there is basically no evidence for voter fraud being a significant factor in US elections.
About 9% of Pennsylvania’s ~9 million registered voters lack a government ID. Pennsylvania’s in-person requirements for voter ID and provisional voting are here. If all of those votes are lost and they break 2-1 Democratic, that would be a net gain of up to ~3% for Romney. The current margins for Pennsylvania are Obama +7%. My guess is that if this margin drops to +3% or below, then Republicans have some chance to flip the outcome there.
Can this be accounted for in the Meta-Analysis? In a limited manner, yes. One way to give you a sense of the maximum possible impact of voter-ID laws is the “+2% for Romney” tool in the right sidebar. Another view comes from using the Meta-Margin, whose accuracy is a few tenths of a percentage point. It’s at Obama +3.0%, right on the edge for a Republican win if they get voter-ID laws in all swing states and if they extract the maximum possible advantage (and if pollsters somehow failed to assess this).
Pollsters will eventually take the new requirements into account in their likely-voter screen. They can ask questions such as “Do you have a government-issued picture ID?” At some level, it feels best to leave that to them.
Thanks to Rachel Findley for suggesting this question.