I think the biggest failure of Republicans in 2012 was not at the presidential level, but the Senate, though both cases represent the same problem.
In the Senate, Republicans lost in a lot of states they had no right to lose in during a fairly neutral presidential year. Look at Missouri, look at Indiana; the fact that Republicans lost or failed to pick up these two seats is entirely their fault, they chose the horrible candidates in those states that then decided to go talk about rape.
It wasn't just that the Republicans were bad, the Democrats did all of the right things. Montana and North Dakota featured very strong Democratic candidates prevailing where many thought they wouldn't. The Democrat's victory in Missouri is partially due to McCaskill cleverly airing 'attack' adds helping Akin by calling him too conservative.
Agreed, it seems to be very understated just how great Democrats did in the Senate in 2012, probably because they "only" netted 2 seats. But that ignores the fact that they had no business even holding the Senate considering how favorable the map was for Republicans, much less gaining seats.
