The War of Southern Aggression.
Free Soilers, settlers of Kansas and Nebraska, immigrants and others of the North viewed it as "The War of Southern Aggression," as southern slave holders launched armed militia/mob invasions out of MIssouri against the non-slave holding settlers and administrators in the Kansas-Nebraska Territories. This is interesting since the Confeds then appropriated the reaction to their bloody mob & militia violence in that western region (which provoked equally bloody terror on the part of insane people like John Brown) for themselves post the Surrender at Appomatox. The Confederacy labeled the Civil War The War of Northern Aggression, though they were the ones who began the violence, in order to expand slaveholding territory.
This is what occured to me yesterday, as I poke around in that long era of national consciousness from the presidency of Polk through the Civil War. I have no idea how right this is though, because I don't know enough about all these issues yet. It's not as though they were taught at all in one's history courses in college or in grad school. You could specialize in them, as a professor publishing or perishing via your scholarship. But academics tend to look at issues in solitary confinement. The connecting of dots among areas of scholarship are left to the 'independent' scholars.
Manifest Destiny and the drive to market expansionism grew parallel with increasing imigration population throughout that same decades, which increased until around WWI, when it was essentially stopped -- until post the Civil Rights era, which put an end to legal Jim Crowe, and that eternal pool of cheap and expendable labor.Southern slavery made the coming Confederacy's region less hospitable for immigrants, due to slaves filling almost all the jobs. So immigrants also looked west to the new lands opening for settlement.
However, as we see distilled in the long and bloody violence of Kansas-Nebraska, as the rest of the nation also proudly believed that Manifest Destiny was the nation's natural right as well as good for the rest of the world (why, yes! you can find much rhetoric that expounds this -- and again, why we NEED Cuba -- for its own good -- and much of South America, and probably Canada too) -- so did southern slave holders believe it was their manifest destiny and obligation to expand slavery into all those regions as well (and again, why, yes! we not only NEED Cuba, but it will be so much better for Cuban slaves and the world that we control Cuba -- not to mention that we then can ensure no cheap slaves will be dumped on US via the vagaries of Cuban national events). Slaves and the slave trade was the foundation of the regional economy.It was during these decades that slavery in the slave states became ever more draconian, and ever more twisted, and the intra-state slave trade ever more profitable, leading to the state of mind that made the belief in slavery like unto a dogma, if not a religion. In other words, the South's thinking on slavery grew into the same irrationality as fringe religions, which in turn provoked the same irrationality in a fringe of the Abolitionists, like John Brown.
National expansion meant not just railroads and immigration settlement, but Southern determination to push slaveholding into those regions because the more territory that was worked via slave labor the greater the fortunes to be made in the investment in breeding and trading slaves.
As well, expanding the territory for slavery -- despite any previous Compromises (very like any treaty with any (Indian Nation was thrown in the trash as soon as their land was looked at by either settlers, the Feds or mining companies) was essential for the South's continuing political domination of the nation in government and cultural policy -- which circularly meant safe-guarding institutional slavery.In the meantime immigrants already facing racial, cultural and economic hurdles establishing themselves in this nation in the face of slavery were natural allies in the Free Soil movement -- though, not, of course, of Abolition, for former slaves would be willing to work at even lower wages than they were. Former slaves would be competitors for the new lands opening west of the Mississippi.
There were so many movements at the time, so many of them in competition and in mutual hostility with each other: Temperance, Know Nothings, Abolition, Free Soilers. What do you think? I haven't researched this enough yet to know whether I'm just blowing wind here.