I realize the main difference in the 1850s was the Republican Party was able to unite people outside the enslavement institutional South through one issue, the Scourge of Slavery. However, we face an existential threat of corporate domination and a climate crisis that needs to ensure people can be employed in a New Deal of people-helping jobs and green-oriented infrastructure redevelopment, and not continue to be tied to fossil fuel production.
Structurally, the national Democratic Party resembles nothing more than an equivalent to Communist-front organizations where, once the New Deal liberals left in the wake of the Stalin-Hitler deal of 1939, they became hollow shells. Sadly, the national Democratic Party remains controlled by major corporate donors and major consultant companies which have largely destroyed the Democratic Party's ties to working people and New Deal values.
However, all the activists across labor, environmental, and antiwar movements continue to be unable to create a new political party. What it is going to take is leadership from already known politicians, as with William Seward, Salmon Chase, and Charles Sumner, and even a Lincoln, who was very well known in Illinois, contrary to the usual way we think of Lincoln coming out of nowhere for the 1860 presidential nomination.
I am also confident that states with decent Democratic Party leadership, such as New Mexico, will quickly find their way to a new party, and eventually gain more political power in areas now dominated by right-wing Republicans.
It is time. Past time. So, Congressional politicians who supported Bernie Sanders' values and/or Bernie, #DitchtheDems.