If there was a 19th century POD (like the Trent Affair blowing up) several interesting butterflies also are likely. First, the curtailment of British investments in the US. IOTL large amounts of capital flowed from the UK to the US in the post-CW US, funding industrial expansion and growth, particularly in the western states. Railroad construction would have been slower and the westward expansion more difficult.
Second, in the later 19th century, there was a tendency for wealthy Americans to marry into titled European families, most often British ones, leading to an Anglophile upper class in the US, part of the development of the "special relationship." The UK might well have not had the Anglo-American Winston Churchill as a result, and Germany might have had more princelings with American family links.
Second, in the later 19th century, there was a tendency for wealthy Americans to marry into titled European families, most often British ones, leading to an Anglophile upper class in the US, part of the development of the "special relationship." The UK might well have not had the Anglo-American Winston Churchill as a result, and Germany might have had more princelings with American family links.