I really doubt the plausibility of averting the Civil War with a PoD after Lincoln's election.
Avoiding a secession crisis after Lincoln's election is unlikely but not impossible. The key is to get South Carolina--as in 1850-51--to hesitate to secede (for fear of isolation) unless some other state goes first. And it is possible that no other state
will go first if South Carolina doesn't. For how this might come about, I will recycle an old post of mine (sorry for links that may no longer work):
***
Could secession have been avoided after Lincoln's election? The usual answer is that *at the very least* South Carolina was sure to secede. And yet, even in South Carolina, there was one very prominent politician who *privately* did not regard the South's prospects in the Union as hopeless, even after Lincoln's victory: US Senator James Hammond. In a letter to Alfred Aldrich just after Lincoln's election, Hammond stated "I do not regard our circumstances in the Union as desperate." True, Hammond preferred a Southern Republic if he could be sure that the other southern states would follow South Carolina in seceding, but he had no confidence they would do so. For that reason, he did not want South Carolina to secede until other states had resolved to do so--advice that *if made public* and followed, could have doomed secession, given that even *with* South Carolina's prior secession, the victories for "immediate secessionists" in the Deep South state secession convention elections were often quite narrow.
Hammond explained why he thought staying in the Union was safer for South Carolina than attempting "go it alone" secession: "the South...can, when united, dictate, as it has always done, the internal and foreign policy of our country." (Note that Hammond is here admitting one of the Republicans' main allegations--that the South, far from groaning under northern oppression, had hitherto dominated the country.) Hammond explained that "at the North, politics is a trade." The spoilsmen "go into it for gain." (This was a typical South Carolina aristocratic view of the "mobocracy" which was seen as prevalent in other states, and especially in the North.) For that reason, no Yankee has "ever been twice elected President." Mr. Lincoln's administration will also break down "before it can accomplish anything detrimental", for its "antislavery agitation" will "not gain them spoils and power." (Quoted in William W. Freehling, *The Road to Disunion, Volume II: Secessionists Triumphant 1854-1861,*, p. 405)
https://books.google.com/books?id=AsjRsGPOXKMC&pg=PA405
Indeed, with delayers in control of both houses of the South Carolina legislature, and with Aldrich having Hammond's letter in his pocket, things looked bleak for the South Carolina ultras. But then came the "incredible coincidence" I described at
http://groups.google.com/group/soc.history.what-if/msg/8b15a54b3f1a3dbd "A railroad had just been completed linking Savannah, Ga., and Charleston, S.C. As the South Carolina legislature deliberated, leading citizens of the two cities took part in a celebration. The Georgians, carried away by the emotion of the moment, pledged their state's support for secession. Suddenly convinced that other states would follow, the legislature moved the secession convention up to December. The 'coincidence,' Freehling argues, changed history. Had South Carolina not taken this step, Unionists might have prevailed throughout the South."
As it was, however, Aldrich decided not to make Hammond's letter public at the secession convention--and Hammond acquiesced. Too much had changed since the letter was written, Aldrich stated. South Carolina was now too overwhelmingly in favor of secession for it to be blocked, and it was therefore better, Aldrich explained, for the state to present a united front to the rest of the world. Had the railroad not been completed just when it was, and had Aldrich promptly released Hammond's letter to the general public, things could have gone quite differently. South Carolina might have decided not to secede until another state did--which might never have happened...
Or it might have. The battle in the Deep South was generally not between secessionists and unionists but between "immediate secessionists" (also called "separate state action secessionists") and "cooperationists." The big question in determining how close secession was to being avoided is to determine whether cooperationism was just an alternate form of secession or--as the immediate secessionists charged--really a disguised from of Unionist "submissionism." The cooperationists claimed that they also favored secession if necessary but that it should be done not by separate state action but by a southern convention which could put final demands to the North and secede if they were not met. One problem with the cooperationists' position is that the more states seceded, the weaker it became. The immediate secessionists could (and did) say, "We are the *true* cooperationists--we are in favor of cooperating with the states which have already seceded!"
If South Carolina had decided to wait for the other southern states, the cooperationists might have prevailed against the immediate secessionists throughout the South. It is easy to say that this would simply result in Secession Later rather than Secession Now. Surely a southern convention would present Lincoln with demands he would not meet--e.g., abandon the Republican position on slavery in the territories. And yet...cooperationism would after all buy time for the Union, and the immediate secessionists were right to suspect this would strengthen the Unionist cause. They felt they had to strike while the South was still panicking over Lincoln's election. If you allow Lincoln to be in office for some time before acting, the panic will subside, southerners will see that slavery had remained unmolested and that the new president was not another John Brown. Even if the proposed Southern Convention would eventually come about, it might be dominated by Upper South moderates whom Lincoln could appease (e.g., by admitting New Mexico to the Union, at least nominally as a slave state, and by indicating his disapproval of Personal Liberty laws).
So, then, a victory by cooperationists in all the Deep South states *might* give the Union a chance. Was such a victory possible if South Carolina didn't jump the gun? I would say that it was because, as I noted above, even in OTL the "immediate secessionist" victories were quite narrow. In Alabama, the secessionists cast 35,600 votes, the cooperationists 28,100. In Georgia, the secessionists won by only (at most) 44,152 to 41,632. In Louisiana, the secessionists prevailed by 20,214 to 18,451. In Mississippi, there were 16,800 votes for secessionists, 12,218 for cooperationists, 12,000 for candidates whose position was not specified or is now unknown. Florida was somewhat more pro-secessionist than, say, Georgia, but even in Florida the cooperationists got about 40 percent of the vote. (My source for these figures is David Potter, *The Impending Crisis.*)
So preventing secession after Lincoln's election is very, very difficult but IMO not *quite* inconceivable.
https://www.alternatehistory.com/forum/threads/wi-no-secessionist-crisis-as-lincoln-becomes-president.424396/#post-15481060
***
So let's say a secession crisis
is avoided. What could Lincoln do to bring slavery closer to "ultimate extinction"? Probably not much, except in the sense of *refraining* from doing some things that a pro-slavery administration might do (e.g., seeking southward expansion). Yes, he might seek to build up the Republican party in the Upper South by the use of patronage, but probably with limited success. After all, his patronage wasn't enough to make the border slave states Republican in OTL; even a state like Delaware where there were few slaves and where Lincoln had received a substantial vote in 1860 went for McClellan in 1864. Lincoln did carry Maryland and Missouri in 1864, but that was largely due to the disfranchisement of pro-Confederate elements. As for the Lower South, Lincoln made it clear that in areas where there were few or no Republicans, he would not attempt to appoint them to office.
What about the slavery-in-the-territories issue? Once Kansas was admitted as a free state, that was pretty much dead so far as the
existing territories were concerned. New Mexico might be admitted as a nominal slave state but one with only a handful of African American slaves. (There was unfree labor in New Mexico--but it took the form of debt peonage and Native American captivity.)There was even less of a prospect for slavery in territories further north. And Lincoln is not going to get the US into southward expansion.
He
will have a chance to appoint some Supreme Court justices--but not as many as in OTL, because with Alabama remaining in the Union, Campbell will presumably not resign. As in OTL, Lincoln would choose McLean's successor, but that would just mean replacing one Republican with another. Replacing Taney and Daniel would make the Court somewhat less proslavery--but still there would still be Campbell, Catron, Clifford, Nelson , Grier, and Wayne. And will a Democratic Senate allow the creation of a tenth seat for Lincoln to fill?
What about the Post Office allowing "incendiary" materials to be mailed in the South? It probably will not make much difference--Southerners will suppress abolitionist mail on their own, by extralegal means if necessary.
Would the very fact that an antislavery party triumphed in the presidential elections have inspired slave rebellions? Unlikely. The slaves could see that local white police power was not shaken.
Looking beyond slavery, what about the tariff? The Morrill Tariff could not have passed if the states that had seceded in OTL had kept their seats in the Senate. (It passed 25-14 with six states and their twelve senators absent: AL, FL, GA, LA, MS, and SC.
https://www.govtrack.us/congress/votes/36-2/s512) All the Republicans in Congress, even combined with protectionist Democrats like Bigler of PA, probably could not have gotten a tariff increase if the South had stayed in the Union.
It is true that a couple of more free states could have been admitted to the Union. But its hard to see why this is an immediate danger to the South, given that western states (even when Republicans) tended to be Negrophobic and skeptical of protectionism.
All in all, it is hard to see how Lincoln's victory could pose an
immediate threat to the South. This doesn't mean that secessionists were wrong to sense a long-term danger to slavery if the South stayed in the Union. There would be more Republican judges in the future, more Republican states, and eventually there could be a Republican Senate as well as House. The few Upper South "Oppositionists" open to fusion with the Republicans--Henry Winter Davis of Maryland, maybe John Minor Botts of Virginia
https://www.alternatehistory.com/fo...n-wins-and-no-secession.494768/#post-20936551 --might become more numerous. Even if they are unlikely to transform their states immediately, still their very existence seemed dangerous to slaveholders who thought white unanimity on slavery was essential to safeguard the institution. More border states might eventually decide on gradual emancipation, Delaware and Missouri being the most plausible. [1] More important, a line would have been crossed--a declared antislavery party could gain control of the White House without the South seceding. This, the secessionists feared, would leave the South so demoralized that they would not be able to organize effective resistance to future antislavery steps. So in that sense secession, though a gamble, was not an irrational one if you put the long-term survival of slavery above everything else. What
was irrational was the fear of immediate disaster the secessionists fostered among Southerners.
So would Lincoln be re-elected in 1864? It's hard to say. The Democrats would have the advantage of being more united than they were in 1860 once the divisive Douglas leaves the scene. OTOH, one of the major arguments against the Republicans in 1856 and 1860--"if they win there will be disunion and civil war"--will no longer be credible.
Moreover, even a return to Democratic rule in the White House would leave slaveholders uneasy , because it was already evident by 1860 that many northern Democrats were as committed i
n practice to the containment of slavery as the Republicans.
[1] It is noteworthy that in 1857 James Rollins, the "Oppositionist" candidate for governor of Missouri, came close to defeating the Democratic candidate.
https://en.wikipedia.org/wiki/1857_Missouri_gubernatorial_special_election Besides Whigs/Americans/Oppositionists Rollins had the support of the emerging Republican Party of Missouri (which was pretty much limited to St. Louis and a few nearby German counties) and many Benton Democrats. "Rollins, himself a slaveholder, did not favor immediate emancipation, but he affirmed that a day might come when Missouri would find it to her economic advantage to convert to a free-labor system."
https://books.google.com/books?id=FbcukKSwqdAC&pg=PA186