you also have to consider that many Americans during the earlier years of the country claimed German ancestry. They made up a good chunk (largest ethnic group after the Irish) of the Regular Army prior to the end of the 19th century, and there was real concern in some quarters about the public willingness to get involved in World War I due to said "German influence." It's also worth noting the impact that the Prussian Army system had on folks like Sherman, Sheridan, and Emory Upton. Most of the regimental reorganization plans that surfaced during the 1880s made at least passing reference to the German "community system" where a regiment would have a home station and conduct its recruiting there. That and the reference to Ohio before the Civil War as "America's Prussia" is certainly interesting...

That said, it's much more likely that the claimed "American character" is really a combination of all these factors...for good and ill. Efforts to ignore that blending, attributing it to one ethnic group or the other, really miss the point. IMO, anyhow.