I just added The Storm Is Here: An American Crucible by Luke Mogelson to the Recommended Reading List.  It is the best effort to date combining the extremist influences on American politics and the possibility of a second civil war.  It outlines the rise of authoritarianism in America and the danger it poses.

Three “companion” books already on the list are: Fascism by: Madeline Albright, Strongmen by Ruth Ben-Ghiat and How Civil Wars Start by Barbara F. Walter.