People often lament that “both parties [in the present-day United States] are the same.” I disagree, but I get where they’re coming from. However, I have to imagine political choice, such as it is, was even more constrained earlier in American history. Maybe that’s an inaccurate assumption, so please correct me if I’m wrong; my assumption comes from watching the BLM, #metoo, and LGBTQIA movements in recent years. Incidentally, I sit here watching a basketball game in which both teams walked off the court during the national anthem, which would have been unthinkable even four months ago.
I ask about the particular period between Reconstruction and the Civil Rights Era because that era is often held up as a relatively tranquil time in terms of domestic politics. That’s not to say there weren’t weighty questions surrounding Black rights, WW2, Japanese-Americans, and others, but I know very little about the scope of debate on those and other issues. I’m hoping someone can educate me. Were the parties “the same” then? What were the serious debates of the time?
Because this is a very broad question - Overton windows move one event at a time, one day at a time, and the time frame covers a century - I believe a broad framework of "rise and fall" to which major events are milestone markers will be most helpful to you. This is a question deserving of a book, maybe multiple books, each with differing interpretations, but I can attempt a outline.
So - what rose, and then fell? A certain kind of consensus that emerged in the Reconstruction years, fell into a succession of crises during the Depression and war years, and crumbled in the 1960's. What was the platform of this consensus? We can examine it by some major policies and trends:
At the start of this period, a personified Columbia is the image of an expansionist US. By the end, Lady Liberty is the preferred flavor of U.S. ideology, and has been for some time.
As we look towards the later years of the period, we see the system make very large directional swings: The economic distress of the Depression creates a wave of socialist policies and labor wins, followed in turn by a post-war backlash in the second Red Scare. The war years motivate a practical need for integrated armed forces, leading to Executive Order 9981, fostering emergence of the civil rights movement. Broad instabilities emerge in the consensus, and the aftermath of the war, combined with the prospect of the next one going nuclear, presents hard challenges to the imperialist dynamic that had been carried on since the Spanish-American war. The 50's, in the end, are tranquil on the surface, and tense internally. The trends had to shift.
By the 60's, a new consensus was able to emerge around neoliberal-progressivism, keeping some of the old trends(consumerism), repurposing others(overt racism becomes covert, progressive causes are diverted to consumer activity), stopping a third group(labor movements, Puritan progressives), and beginning some new ones(the broad array of postmodern thought, and the centering of STEM fields in education). This is the post-1970 consensus that is currently lived in and in crisis, and thus is hardest to articulate in full.
Even with all this scope, I haven't touched on the political parties, but I would approach that question by noting that politicians are opportunistic and latch on to the trends, so if you know the trends you can identify the debates.