During the the 2008 election the political book map reflected the deep divide in the country between conservative (RED) voters and liberal (BLUE) voters. There were no connections, nor any intermediaries between red and blue books -- each cluster was completely closed off to the other. There was a separate cluster of people reading books on the then new candidate -- Obama, but they were not interested in reading/purchasing other political books (upper left corner of network map below).
2008 Political Book Network Map
The third bridging book was a surprise! The Little Blue Book is intended for a progressive audience -- it is a handbook for how to argue effectively with the right wing. So, you would expect it to be firmly in the center of the dense blue cluster, right? Wrong! It has both blue and red readers! I checked all editions of the books -- hardback, paperback and Kindle. For the Kindle version, The Little Blue Book was connected (also bought) with other blue books, as expected. It was with the paperback edition where I was surprised -- 4 of the first 10 also-bought books were red books! Amazon shows their also-boughts by decreasing count/volume, therefore there were many instances of readers of certain red books were buying The Little Blue Book. Why is this so? Maybe the right wing is trying to understand the left wing and reading their blue handbook -- similarly to how they read the far left book Rules for Radicals during the 2008 election campaign.
2012 Political Book Network Map
This year we also have books about the candidates -- their biographies and positions on major issues. Obama has the same set of books as last election, Romney has his No Apology series, and Romeny's running mate is written up in the Young Guns book. Potential voters appear to be reading books about both of the candidates -- Amazon readers are buying books about Romney and Obama together! See books in upper left frame (2012 Candidate biographies) above.
Another pattern is different in 2012 than in 2008. Now, people reading about the candidates, are also reading other political books. The pattern is positive for Romney -- people reading about him are reading other red books -- not so, for Obama. People reading his positive biographies and position books are also reading polemics attacking Obama. The most influential anti-Obama book in the above network is Obama's America -- it is read by potential voters who are reading about both Obama and Romney. See the link patterns in the upper left corner of the above diagram.
Even though the two book networks are connected, we still have a polarized voter base -- those are two strongly defined communities. Running one of the network metrics from InFlow software, reveals two tightly defined clusters. The E/I Ratio (External/Internal) is near -1.0 for both the blue and red groups indicating two exclusionary communities. Polarization persists in America.
Can we use these network maps to predict the election? Probably not. The main insight I get from these maps is that the 2008 election provided a more clear cut choice for voters. Although supporters of each candidate today would also say the choice is clear this time around (they always say that), the data does not support that. The bad news for Obama is that in 2008 people were mostly reading positive books about him and in 2012 they are reading both positive and negative books about him. Are these that small percentage of undecided voters who will likely decide this close election? I bet each campaign would love to know who these Amazon readers are... and these readers may want to know who each other is!