Imagine this: the 1863 Chattanooga Campaign goes better for the South. As a result, the Atlanta Campaign starts later and lasts longer. On Election Day, 1864, Lincoln loses to George Pendleton. In December, a month after election day, Atlanta falls as Lincoln is determined to continue the fight until inauguration day. In March, newly-elected President Pendleton signs a peace accord with the Confederacy. Virginia (sans West Virginia), North Carolina, South Carolina, Georgia, Florida (sans the Florida Keys) Alabama, Mississippi, Louisiana, Arkansas, and Texas would be part of the new CSA. Tennessee would remain in the Union, and the Mississippi would be internationalized, with any attempt to close it to Union trade being construed as a declaration of war. On May 9, 1865, this peace accord is approved by the Senate.
What happens to the Union?
The Confederacy?
The slaves?
The native Americans?
disscuss
Pendleton may or may not survive his Presidency, which is likely to be viewed as a disaster. By 1866, Republicans have retaken the House of Representatives and slavery is going to be killed by Constitutional amendment either with Pendleton in office, or quite possibly after his death in office, or perhaps after his term ends.
The thing is, the Civil War doesn't really end, it just stops being a formal conflict. Abolitionists want to continue the war, but if they can't officially do that, they'll join what is likely a full scale insurgency inside the Confederacy itself.
The Election of Salmon Chase to the Presidency in 1868 probably means a re-ignition of the Civil War; and its a phase that goes very well for the Union. By 1872, Chase is re-elected with the great reunion of the United States as a personal glory, but doesn't live that long before he himself dies in office. His Vice President, one of the heroes of Gettysburg, Joshua Chamberlain, assumes the Presidency in May 1873.
Reconstruction by this point is a fundamentally different issue than in 1865. The Civil War simply went through a series of phases between war, guerrilla war, and redeclared war--and a large part of it is USCTs, Contrabands, Unionists and Abolitionists. There's no Lincoln even beginning to consider a moderate approach to reconstruction. The slaves are freed, guaranteed rights by Constitutional Amendments, and Confederate rebellions are stamped out.
No Jim Crow, as the freed slaves deserve a lot of recognition for their role in keeping the Union together. But there are confederate rebellions into 1900 as the Republicans hold power for a whole generation. It's even possible that the Democrats, tarred by Pendleton, wind up disappearing as a force for national politics and a different party of labor unions and poor farmers emerges.
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The Confederacy's woes don't end at the peace table; Pendleton can order US troops out of its territory. But he can't order contraband's back on his chains and regaining control of locations like Atlanta, New Orleans and Montgomery will mean fighting ex-slaves by the thousand.
Nor can Pendleton stop Unionist and Abolitionists from supplying those contrabands and attempting to fan larger rebellions. This will also mean things like Louisiana attempting to counter-secede from the confederacy as New Orleans would be occupied, for the moment, by the same--and with some hope of getting the USA to back them, as the Mississippi is at stake.
This all means continued military action is necessary. Slavery can be reinstated, but nothing less than a major military campaign from a razed Atlanta to New Orleans.
Jefferson Davis leaves office facing serious issues of debt, internal security, and a broken economy. Unable to demobilize his army, struggling to rebuild when the labor supply is in open rebellion, and probably facing some horrible spiral of taxes, inflation and unsustainable finances, Davis can at least claim that he won the war.
His successor, Nathan Bedford Forrest, is initially the right man at the right time. Able to gain the buy-in of poor whites as a man who clawed his way to the top, Forrest is a force for Confederate solidarity in the ongoing attempt to reenslave free blacks, chop out Unionists, and restore order. But he doesn't have time.
Pendleton (or his successor, if he is killed in office) gets the boot in 1868. President Salmon Chase takes office, and quickly issues at first demands, before upping the ante to an ultimatum: Unionist territory inside Confederate borders belongs to the Union.
It's a darn fine mess for a nation that claims that it has the right to secede over states' rights to deny the same on its own, and these territories (Northern Alabama, North Texas, the Appalachians) also include solid defensive ground.
Forrest refuses. To accept would essentially spell the end of the Confederacy piecemeal, and he knows it. He could consider a foreign alliance, but the UK probably prefers the Union over the Confederacy and Bismarck's Prussia is kicking Napoleon III across the board. No one is offering.
With the Confederacy barely having any repairs finished, the Union's initial advances in 1869 reveal just how much stronger the Union is economically than the South. The Union has replaced its losses, improved its weaponry, and learned well from its mistakes in the previous war. The Confederacy, on the other hand, is broke, unable to fully repair itself and still faced with a hostile internal threat.
This war is a crusade to reunite the Union and Abolish Slavery. Meanwhile, the Confederacy is struggling to hold to the idea of slavery as a positive good. Forrest himself is a slave merchant, as committed to that cause as Jefferson Davis. As the situation grows more desperate, the Confederate Propaganda grows increasingly shrill about the "Right Nature of God".
The second round of the Civil War has a lot of the best Union commanders still in ranks, although I've suggested that Chamberlain would have gone into politics after his repeated injuries. Meanwhile, Robert E. Lee has died and Confederate command is perhaps equal.
The fortunes of war lead to repeated defeats for the Confederates, who face more frontage than the previous conflict, fewer men to do it, and a dedicated fifth column in terms of the slave system. Forrest flees with a bunch of precious metals to Brazil in 1872, where he lives out his life in exile. A series of trials begin for the highest traitors to the Union, amongst them Jefferson Davis, John C. Breckinridge, Forrest himself in absentia, and other figures like Judah Benjamin, Alexander Stephens, and most governors who decided to secede.
This makes for interesting viewing, although President Chamberlain commutes executions for those found deserving of that fate to life imprisonment.
The OTLish direction of reformers heading South to try to help the free blacks and build a new direction for the region has federal support under a tough reconstruction system that enfranchises former slaves. With no Forest, there is no KKK, but several things LIKE it do get repeatedly stamped out.
The historical narrative is clear: Slavery sunk the South. They can't win hearts and minds around the world for their cause, they can't win peace at home, they can't even win the limited normalcy that existed pre-1850. With former slaves serving an indispensable role in keeping the pressure on the rebels, they're due a cut of the victory. It will be deeply resented and likely one of the great antagonisms into 1900, but the cause has failed.
Many slaves died as brutal means were applied against their rebellions. Many were injured as a result of the ongoing war. But post-war, they get a better deal; guaranteed citizenship, state governments that use their power as a bloc in the era of reconstruction to build a new order, and also the option to head west.
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Native Americans are still in serious trouble, eight years delay to the contrary. The issue isn't so much Stand Watie and pro-Confederate Indians; it's the very OTLish concern of politically powerless minorities having stuff that other people want.
The PoD also doesn't stop the likes of John Chivington from killing innocent Indians, although it would reroll the Indian wars of the 1870s a bit. The same problems remain, and things probably get very ugly.
The upshot is the USA may be somewhat less racist in the long run, if Reconstruction is forced to work instead of being called off for political reasons. But Indians had almost nothing going for them in OTL all the way to the time of FDR. It's not implausible that things get better earlier, but wanton massacres are still in the lineup.
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All told, I think the likeliest outcome of a narrow confederate victory is a quick sequel and a decisive defeat. There are many new heroes; there are many dead zeroes.
George Armstrong Custer doesn't die to a giant band of plains Indians.
Thomas Edison is of age to serve in the Union army.
Presidents Grant, Hayes, Garfield, Arthur, Harrison and McKinley were all military men in the Civil War; each of their fortunes is on the dice.
The world very quickly leaves OTL in favor of its own direction.