Here's an apocalypse to watch out for:
More than 758,000 registered voters in Pennsylvania do not have photo identification cards from the state Transportation Department... the new numbers, based on a comparison of voter registration rolls with PennDot ID databases, shows the potential problem is much bigger, particularly in Philadelphia, where 186,830 registered voters - 18 percent of the city's total registration - do not have PennDot ID.
A little perspective. In 2008, Barack Obama won Pennsylvania by the biggest majority of any candidate since 1972* -- 620,478 votes. So, the total number of voters lacking ID is greater than that. Most of Obama's margin came from his landslide in Philadelphia County -- 478,759 votes over John McCain. So, the total voter bloc that lacks valid ID is about 39 percent as large as the Obama-McCain margin.
You see the problem for Obama. It's entirely possible that, on election day, a majority of Pennsylvanians will want to vote for the Democrat, but a few hundred thousand of them will lack the tools to do so under the new ID law. Student IDs, military IDs, and passports will be enough to get you counted, but only the first kind of ID disproportionately favors Democrats.
*I'd originally, mistakenly written 1984, but Obama's 54.5 percent in PA was larger than Reagan's 53.4 percent.