Between 1850 and 1890, the number of German immigrants increased rapidly, outnumbering the Irish by 1880. For the most part, the reason Germans came to the US were no different than any other group of immigrants (religious freedom, opportunity, etc), it's just that there happened to be a lot more Germans in general. There was already an established German community in the US even before the Revolutionary War, estimated at around 9% of the population (German American).
A Princeton PhD, was a US diplomat for over 20 years, mostly in Eastern Europe, and was promoted to the Senior Foreign Service in 1997. For the Open World Leadership Center, he speaks with
its delegates from Europe/Eurasia on the topic, "E Pluribus Unum? What Keeps the United States United" (http://johnbrownnotesandessays.blogspot.com/2017/03/notes-and-references-for-discussion-e.html). Affiliated with Georgetown University (http://explore.georgetown.edu/people/jhb7/) for over ten years, he shares ideas with students about public diplomacy.
The papers of his deceased father -- poet and diplomat John L. Brown -- are stored at Georgetown University Special Collections at the Lauinger Library. They are manuscript materials valuable to scholars interested in post-WWII U.S.-European cultural relations.
This blog is dedicated to him, Dr. John L. Brown, a remarkable linguist/humanist who wrote in the Foreign Service Journal (1964) -- years before "soft power" was ever coined -- that "The CAO [Cultural Affairs Officer] soon comes to realize that his job is really a form of love-making and that making love is never really successful unless both partners are participating."