Complex sentence: Eric Alterman, writing a book review of "The Race Beat" (2006) in The Nation discusses how Carter and other southern jounalists were "moderate defenders," in short, apologists for the South during the pre-civil rights era.
Split into simpler sentences: Eric Alterman, writing a book review of "The Race Beat" (2006) for The Nation discusses how Carter and other southern jounalists were "moderate defenders," of the South. That is, they were apologists for the South during the pre-civil rights era.