I learned about Willich from leftist commentator Matt Christman, but would love to know more. Though Willich had a wildly interesting career fighting in civil wars on two continents, there doesn't seem to have been much research into his life.
The impact of the German 1848ers and exiled leaders like Willich or Carl Schurz for the Union is actually pretty well known in the historiography of the Civil War. German-Americans were quite prominent in the machinations preventing Missouri's succession and a considerable number of Germans enlisted in Union regiments led by 48ers. Among some left-ish political commentators, the connections of these individuals to Marx is something that connects Marx to abolition and wider cause for human rights. The 48ers and their Marx connections also feature somewhat on some neo-Confederate apologia like James Ronald Kennedy to tar Lincoln and the Republicans with an association with this great Feind. While the neo-Confederate apologia is tripe, drawing a connection between Lincoln, German exiles, with Marx and the British trade unions is also a bit dicey history and projects a sort of transnational movement that did not quite exist.
The reality is that German support for the Union was a complex affair. A good many of the 48ers did actively support both the Union, free soilism, and the cause of abolition. German voters were a component of Lincoln's electoral victory in 1860 and delivered votes in key states. The 48er leaders in particular stressed that after the failure of the 1848 Revolutions that the US was one of the best hopes in the world for democracy. Additionally, a number of German immigrant leaders saw that fighting in the war would be a victory against nativism and know-nothingism. Willich framed his appeal for volunteers for 32nd Indiana Regiment as showing the rest of the US "what patriotic Germans could do." Raising companies for federal service also allowed for greater participation of Germans within the federal system and support in Congress. There was also a fairly strong grass-roots revulsion against the institution of chattel slavery among German immigrant groups. Letters from German soldiers on duty during the ACW do register a degree of disgust with slavery. This coincidentally mirrored some of the sentiments of Hessian mercenaries during the Revolutionary War who were likewise ill at ease with slavery and some 131 runaway slaves were allowed to enlist in the Hessian Army and some returned with their regiment back to Hesse-Kassel.
But there was more to the German-American community than the 48ers. The exiles often formed the charter generation of German immigrants and naturally were the senior political leaders of the community by Fort Sumter. Motives for volunteering for federal service mirrored that of other immigrant groups; enlistment bounties, the need for work, peer pressure, and other less noble motivations played a role along with the desire to preserve democracy and end slavery. Additionally, free-soilism does not automatically translate into sympathy for blacks or a more racially-equitable society. Carl Schurz's postwar political trajectory shows some of these contradictions. In the tumultuous politics of the 1850s, Schurz was quite vocal in his opposition to slavery as an impediment to American progress. But once a Senator in the 1868, he backed away from Radical Reconstruction and opposed Grant's use of military force against the KKK. While Schurz was hardly the first politician to do a volte-face on his political positions, the ease with which this prominent German-American did so does call into question the nature of antislavery within the German-American community. Moral revulsion towards the institution was also wrapped up in various other aspects of German-American identity. Part of the response to nativism was to argue that Germans were the true bearers of democratic ideals and freedoms in the country. Schurz and other 48ers often castigated slavery as an American vice in their private correspondence, maintaining a certain level of old-world condescension about American materialism and lack of culture. The 48ers themselves were not always the champions of progressive politics either. One of the faultlines in the 1848 Revolutions in Germany was the issue of non-Germans within a future German state, with many of the Paulskirche liberals tacking to a fairly chauvinistic attitude towards those not lucky enough to have been born German. Despite having fought the forces of reaction, a number of the aging 48ers welcomed Prussia's victory over France in 1871. Willich actually volunteered his services to Prussia in the Franco-Prussian War, but the Prussian Army had little use for a disabled 70-year old veteran.
Pace The Communist Manifesto's declaration that communism was "a spectre haunting Europe," the radicals of 1848 were a diverse and often incoherent lot and some were not even that radical. Terming them "communist" not only projects a retrospective form of politics onto them, but loses the nuances of what "communist" or "radical" meant in 1860. Both James K. Polk and the US foreign service were enthusiastic about the 1848 Revolutions and sent Andrew Donelson as Envoy Extraordinary and Minister Plenipotentiary to the Paulskirche parliament. John C. Calhoun believed that of all the states in Europe, Germany was the one most apt to become an American-style republic with a constitution, writing to his brother-in-law "I look to [Germany] to save Europe." For many within the Lincoln administration, the proactive response of German-American leaders to preserve the Union was a sign that the politics of 1848 were not a grand departure from the American system, but rather a confirmation of the universality of American ideals.
Sources
Efford, Alison Clark. German Immigrants, Race, and Citizenship in the Civil War Era. Cambridge: Cambridge University Press, 2013.
Jonas, Manfred. The United States and Germany: A Diplomatic History. Ithaca (N.Y.) [etc.]: Cornell University Press, 1984.
Keim, Jeannette. Forty Years of German-American Political Relations. Philadelphia: Printed by W.J. Dornan, 1919.
Reinhart, Joseph R. August Willich's Gallant Dutchmen: Civil War Letters from the 32nd Indiana Infantry. Kent, Ohio: Kent State University Press, 2006.