I recall reviewing the popular vote figures down through the years. The remarkable thing about the 2012 presidential election is that, setting aside for the sake of argument the Civil War election of 1864 (when the 11 states of the Confederacy did not participate) and the election of 1944 (when the country was in full-scale war mode in WWII), 2012 was the first time in history since popular votes were tabulated where fewer total votes were cast than in the previous election!
So how can you account for that, other than (1) many stayed home or (2) quite a number of votes that were actually cast got rubbed out of the totals due to chicanery?
The missing voters were Democrats. The meme in 2012 was that *conservatives* stayed home, but Romney got a million more votes than McCain from a smaller electorate.