I don’t think this is what this article is about, primarily, but this bit just POPPED out at me:
«The [Democratic] party contained within its ranks not only a growing cohort of Northern liberals but also a powerful faction of racially and economically conservative Southerners. The latter, advantaged in Congress by the seniority system, worked with Republicans to bottle up legislative proposals for civil rights and labor reform.
Such efforts helped account for the era’s uniquely high levels of bipartisanship and low levels of party polarization»
People pining for the old days of bipartisanship and collegiality might actually be pining for the above without knowing it.
Kind of like the warm fuzzy thoughts of “reconciliation” after the Civil War that left black people out.
Here, Read This 