Kishnevi has closed his comments, so I actually have to post something here.
He makes an interesting point that the America of the 1890s was much more like now than that of the 1870s because of external technological and geopolitical factors. All true, but he really doesn’t tie that to a difference in thinking, because he neglects the various side-dramas of that Big Picture. For example, America as an industrial powerhouse required importation of lots of cheap labor, primarily from Slavic countries, who both brought in and were susceptible to Marxism. We were also digesting the Germans of ’48-65, and adding to them, and in spite of being one, I have to admit that the German influence on America was not entirely beneficial. (Proponents of free immigration of Latinos ignore the German experience, because to their minds, there was no downside to adding masses who were recently serfs to a country founded by Celtic rebels.) Mass immigration called forth public education (beginning with the Irish in the 1850s) to teach new citizens English and the American culture, or at least the government-supported myth version of American culture. Likewise, America as a military powerhouse was also related to industrialization. We needed markets for our goods and sources for raw materials, in an age where tariffs were falling, and colonialism was mercantilism by other means.