So, what happened in the 1850s was: suddenly, after all those years, such Northerners began to see slavery as not just some quaint Southern institution, but as a growing, expanding existential threat to them. I'm a little vague on why you think you need to say this, since it's pretty much what I said in my post.
The point is that during the 1850s both North and South began to think of themselves as threatened by the other. The South a few years before the North, which is why they insisted on the various measures to protect, as they saw it, the future of slavery, from 1850 on.
The irony, of course, is that by doing so they created the very opposition to the institution that they thought they were heading off.
But I think the most relevant factor in the history of the 1850s, in many ways the most interesting decade in American politics, is that both sides of the emerging North vs. South confrontation wholeheartedly believed they were acting defensively against deep-laid plots of the other side.
The truth, of course, is that while there were no doubt abolitionists and proslavery fire-eaters attempting exactly that, at the start of the decade they were all very much on the fringes. Only as the decade progressed did they move towards greater influence and eventually control.
The Fire-Eaters, of course, got control of the South in 1860, the Abolitionists took two or three more years to get equal influence in the North.
Sherman Logan:
"I'm a little vague on why you think you need to say this, since it's pretty much what I said in my post." I'm willing to concede that our differing opinions may be only matters of emphasis.
If I understand correctly: you wish to emphasize that where the US was a fully functioning, compromising-as-necessary, representative republic before, say, 1850 -- after that date we became more fearful to protect our regions' interests, resulting in less compromise, more dysfunction and eventually secession, right?
My point has been to show that before 1850, really, before 1860, national politics were dominated by the alliance of Southern Democrat Slave-Power and Northern Democrat Dough-faces (big cities, immigrants).
This can be seen especially clearly in Andrew Jackson's election in 1828, but also clearly in several other elections (i.e., 1796, 1856).
Southern Democrat dominance allowed the Slave-Power to force critical compromises (1850) and rulings (Dred-Scott) which increased slavery's legal protections outside the South.
That in turn drove Northerners to support an anti-slavery political party, Republicans, and the rest, as they say, is history...
Bottom line: I don't agree there was no north-south political split before 1850 (or any other date), only that the north-south split was long moderated by Northern Democrat voters, who became less and less "dough-faced" and more "Wide Awakes"*, especially after Dred Scott in 1857.
*"Wide Awakes" = 1860 young Republicans.
