Hramblings: Newspaper endorsements and who elects the president

Based on candidate rhetoric you'd believe that the country is primarily composed of lifelong commited members of the Democratic or Republican parties. This map of newspaper endorsements and the table of shifts from Bush to Obama reminded me of a discussion in my political science class. Clinton Rossiter breaks down each parties members into groups. The interesting part is that the president is elected by the groups Rossiter calls the habitual and occasional electorate. These are the people that participated in the primary for that party and those that voted for that parties candidate in the previous election cycle.