Support for Jeffersonian Hamiltonism was Republican Party consensus from 1815-1824, shared by Clay and even Darth Calhoun. It was based on what little worked for the U.S. during its drubbing 1812-1815. After 1824, supporters of the American System coalesced into the Whig Party. Lincoln loyally supported that party and its platform from the beginnings of his career until its break up in 1852. He helped implement the American System during the first years of his administration.

The event that precipitated Lincoln’s rise was his angry reaction to the passage of the Kansas-Nebraska Act in 1854. That act created an opportunity for control of the General Government to stay with the South even though long-term population growth favored the North. If popular sovereignty flipped enough states in the West, the South would still have a tie in the Senate and, through the 3/5ths compromise, a larger share of the House than their free population warranted.

It had been pushed through Congress by his old friend from the Illinois judicial circuit Stephen A. Douglas. Lincoln, knowing he could whip Douglas, immediately challenged Douglas to a series of debates. Douglas, knowing Lincoln was (then) a political non-entity, refused. Lincoln later got his chance to confront Judge Douglas but, in the interim, he and others in the midwest formed the Republican Party to thwart one-party rule.

In 1859, a group of influential Louisianans, including Braxton Bragg, founded a military academy. The first superintendent was a Yankee from Ohio, a friend of Braggs. Though this Yankee thrived in the position and liked and even admired the South, he was opposed to secession. When it came to Louisiana, he resigned his position and headed North. He later wrote what I consider the the best rationale for why the South deserved to lose the War of the Rebellion:

You cannot qualify war in harsher terms than I will. War is cruelty, and you cannot refine it; and those who brought war into our country deserve all the curses and maledictions a people can pour out. I know I had no hand in making this war, and I know I will make more sacrifices to-day than any of you to secure peace. But you cannot have peace and a division of our country. If the United States submits to a division now, it will not stop, but will go on until we reap the fate of Mexico, which is eternal war. The United States does and must assert its authority, wherever it once had power; for, if it relaxes one bit to pressure, it is gone, and I believe that such is the national feeling.

Sherman, though the adopted son (and son-in-law) of a Whig senator and cabinet secretary and younger brother of Republican party stalwart Senator John Sherman of Ohio (and the later Antitrust Act), was not fond of Lincoln. However, he and Lincoln both abhorred the potential extension of the European state system into the Americas. That would only happen if the Union fell apart, as Lincoln observed in an 1838 speech:

Shall we expect some transatlantic military giant to step the ocean and crush us at a blow? Never! All the armies of Europe, Asia, and Africa combined, with all the treasure of the earth (our own excepted) in their military chest, with a Buonaparte for a commander, could not by force take a drink from the Ohio or make a track on the Blue Ridge in a trial of a thousand years. At what point then is the approach of danger to be expected? I answer. If it ever reach us it must spring up amongst us; it cannot come from abroad. If destruction be our lot we must ourselves be its author and finisher. As a nation of freemen we must live through all time or die by suicide.