The Class First Orientation of American Socialism

Class first orientation so characterize late 19th and early 20th century American socialism. Was it predetermined by the writing of say Marx, or was it more over-determined by what a white-led socialist movement would look like in the settler colony? Some German emigrays who came to the U.S. were class first; others saw slavery as fundamental movement to build class power into over-the-toplism. So they're both class first, but it's just like who's the class.