If political book-buying habits were a good gauge of voters' electoral preferences, Mitt Romney would be a very happy man.

A new Amazon.com feature called the Election Heat Map 2012 (flagged by our Post colleague Mike Rosenwald) divides best-selling political books into conservative (red) and liberal (blue) categories, then tracks sales in every state.

And the country's reading habits appear to be much more conservative than its voting patterns.

Amazon's map assigns each state a shade of blue or red depending upon how many "red" and "blue" books have been purchased there during the last 30 days. The map is predominately red, save for five Eastern states and the District Of Columbia, which are blue, and Pennsylvania, which is evenly split. Nationally, 56 percent of purchases were red books while 44 percent were blue books.

Right now, the best-selling "blue" book is “A People's History of the United States: 1492 to Present,” by Howard Zinn, while the top "red" book is “The Amateur,” by Edward Klein.

How did Amazon decide which books fall into the "red" and "blue" categories?

"The Amazon Books Editorial team pulled extensive lists of best-selling books in relevant categories and vetted them using a variety of tools for clear partisan leaning, separating them into red and blue categories. Many books, of course, have no clear political bias, and therefore were not included. The top 250 titles in each list will power the Heat Map, based on customers’ book-buying habits," the company said in a release.

It's clear that a state's red or blue status on the Amazon map does not exactly correlate to the way it is expected to vote in November. For instance, the entire West Coast is red, even though President Obama is expected to carry California, Washington and Oregon with ease.

And it's not a perfect science. Books not purchased via Amazon aren't taken into account. Additionally, as the company notes, there are books that don't neatly fall into either the red or blue category. (The Fix boss's new book, for example!)

But the map does appear to reaffirm that when it comes to certain mediums, conservative/liberal preference levels don't always mirror what the country does at the ballot box. Talk radio, for example, is a conservative-dominated domain.

While Amazon's map suggests an overall preference for red books, it's notable that Obama's "The Audacity Of Hope" easily outpaced Romney's "No Apology: Believe in America" during the last 30 days.