Lauded as a hero in his native land for his sensational but ultimately unsuccessful exploits during the 1848 German Revolution, Franz Sigel -- who immigrated to the United States in 1852 -- is among the most misunderstood figures of the American Civil War. He was appointed by Abraham Lincoln as a political general in the Union army, a move that successfully galvanized northern support and provided a huge influx of German recruits who were eager...