"In the summer of 1932, the Weimar Republic was on the verge of collapse. One in three Germans was unemployed. Violence was rampant. Hitler's National Socialists surged at the polls. Paul von Hindenburg, an aging war hero and avowed monarchist, was a reluctant president bound by oath to uphold the constitution. The November elections offered Hitler the prospect of a Reichstag majority and the path to political power. But instead, the Nazis lost two...