See Lincoln's famous "House Divided Speech" of 1858.

Let him consider not only what work the machinery is adapted to do, and how well adapted; but also, let him study the history of its construction, and trace, if he can, or rather fail, if he can, to trace the evidences of design, and concert of action, among its chief bosses, from the beginning.

Lincoln alludes to a conspiracy of ringleaders whose aim was to divide Americans by agitating the most contentious sectional political dispute of the Early Republican and Antebellum periods of 19th Century America. And how did they agitate?

its advocates will push [slavery] forward, till it shall become alike lawful in all the States, old as well as new--North as well as South. Have we no tendency to the latter condition?

It wasn't the slavery abolitionists, but the rather the slavery expansionists who were guilty of instigating the agitation. The abolitionists only increased their resolve in response to such agitation, which the leaders of the slave states had continually insisted that they were working on gradual emancipation and abolition, whereas their actions proved the exact opposite.

It will throw additional light on the latter, to go back, and run the mind over the string of historical facts already stated. Several things will now appear less dark and mysterious than they did when they were transpiring.

We can not absolutely know that all these exact adaptations are the result of preconcert. But when we see a lot of framed timbers, different portions of which we know have been gotten out at different times and places and by different workmen [...] and when we see these timbers joined together, and see they exactly make the frame of a house or a mill [...] we can see the place in the frame exactly fitted and prepared to yet bring such piece in

Where there's smoke there's fire... If it walks like a duck and quacks like a duck. Hindsight allows more critical analysis and putting the puzzle pieces together to explain how and why events happened as they did.

Welcome or unwelcome, such decision [to declare slavery legal everywhere] is probably coming, and will soon be upon us, unless the power of the present political dynasty shall be met and overthrown [...] To meet and overthrow the power of that dynasty, is the work now before all those who would prevent that consummation.

Predicting, warning of impending strife if the slavery-expansionists agitators were permitted to continue chipping away at achieving their true goal. All the Republicans, all Lincoln aimed to do, was to prevent such an evil by winning at the ballot box, which they did. So the sore loser agitators gaslit and suckered hundreds of thousands into becoming rebels in defense of their unjust, immoral and evil cause. The deeper rabbit hole, is figuring out the real answer to cui bono? Not just Americans with power... mere puppets of international masters. A story for another day...

For additional historical context, and a more in-depth analysis of the slavery-agitating Disunion conspiracy Lincoln alluded to, also see

Speech on the Dred Scott Decision

Speech on the War with Mexico