If Lincoln lost 1864?

[Sir Mohamed]

Would the US really get dissolved since McClellan wanted to end the civil war through negotiation? This seems to be common belief, but one thing needs the be considered here: even if Lincoln lost the 1864 election, he would have been prez for another 4 months. He was still commander in chief and could have continued the war and pressured to speed up conquest of confederate territory. Even IRL, the Confederacy was pretty much done by March 1865, when his 1st term expired. I find it doubtful McClellan would have negotiated separation with a de facto defeated union of states.

[Cassius]

As you say, Lincoln would’ve been in for an additional four months and was on the record as saying that, if defeated by McClellan, he’d still try and finish the job of destroying the Confederacy. Given that, in real life, the surrender at Appomattox Court House took place only a month after Lincoln’s inauguration, it’s perfectly possible that they would’ve folded regardless of a Democratic victory (indeed they might’ve been more willing to). Of course, if McClellan did win, I’d assume the Democrats would’ve swept to majorities in the House and Senate on his coattails, which would presumably have butterflied away the 13th, 14th and 15th amendments and Radical Reconstruction, so that would have had massive ramifications for the future regardless of victory being achieved.

On the other hand, in order to get a McClellan victory you’d probably (among other things such as reducing the soldier vote to an 1862 level) need to butterfly away the Union’s victories in the late Summer and Autumn of 1864 (the fall of Atlanta, the destruction of Jubal Early’s army etc), so assuming that McClellan did win then the Confederates would likely be in a much better strategic position meaning that both peace negotiations and a Union recognition of Confederate independence would be more likely, the latter perhaps precipitated by Anglo-French recognition of the latter’s independence.

Contra to that, as far as I’m aware McClellan’s stance was that he was prepared to support peace negotiations provided that they resulted in the return of the Confederate states to the Union, with or without slavery, which would not have been an outcome acceptable to most southerners even in 1864-65, and especially not to the Davis administration. This was the same position as that of a lot of the War Democrats and even some of the Peace Democrats (at least it was the public position of the latter, in private a lot of them were sanguine about Confederate independence). Assuming the peace talks between the two governments foundered upon this issue, the war may have dragged on longer, especially if McClellan declined to prosecute it as vigorously as Lincoln gave Grant and Sherman free reign to do in those last months of the war. Alternatively, if McClellan had agreed to Confederate independence, it’s a possibility that the army/Radical Republicans would not have accepted this, and this may have opened a second dimension of civil conflict up in the North, as many had feared would happen as a result of the activities of the Copperheads earlier in the war.

[Unconditional Surrender Truman]

Cassius has already summarized the actual history admirably, so I will just add that McClellan's hopes rested more-or-less entirely on the forecast for a speedy Union victory on Election Day. Lincoln's oft-quoted memoranda committing his cabinet to an orderly transition to a new administration in the event of his "likely" defeat was written in the summer of 1864, when the Union war effort was at a stand-still. The fall of Atlanta changed all that and revived Northern morale ahead of the November elections. All of this is to say that if McClellan is president-elect on November 9, it is most likely the result of a string of military defeats for Sherman in Georgia or Grant at Petersburg —in which case the prospects for an extended war improve considerable, not because McClellan would necessarily have agreed to Confederate independence, but because of his historically well-documented incompetence.

That said, the Confederate military position was so dire in the fall of 1864 that even if they do manage to hang onto Atlanta for a few more months, it is hard to see what the long-term plan was short of the immediate retreat of all Union forces back across the Mason-Dixon line. Perhaps McClellan would have ordered such, but with four months between Election Day and Inauguration Day, I doubt how much of an impact he would realistically have been able to have. The more likely outcome is that slavery is not formally abolished until 1869 at the earliest, since Lincoln as the outgoing president would lack the necessary political capital (and appointment powers) to secure passage of the Thirteenth Amendment before March.

[brucejoel99]

Would the US really get dissolved since McClellan wanted to end the civil war through negotiation? This seems to be common belief...

But it's a wrong belief. McClellan is on record as stating that he'd never accept a permanent dissolution of the Union:

[T]he Union must be preserved at all hazards. I could not look in the face my gallant comrades of the army and navy who have survived so many bloody battles, and tell them that their labors, and the sacrifices of so many of our slain and wounded brethren, had been in vain, that we had abandoned that Union for which we have so often perilled our lives. A vast majority of our people, whether in the army and navy or at home, would, as I would, hail with unbounded joy the permanent restoration of peace on the basis of the Union under the Constitution, without the effusion of another drop of blood, but no peace can be permanent without Union.

In fact, one could go so far as to say that McClellan couldn't afford to give up on winning the war even if he wanted to, given that a decisive majority of the North (the entirety of the Republican Party & even a majority of Democrats) still favored the restoration of the Union, even by war if necessary. Even the 1864 Copperhead-authored Democratic platform sought to restore the Union on the basis of "the federal union of the states," & even if one were to (erroneously) regard the adopted "peace platform" as a "peace no matter the cost" platform, McClellan repudiated the adopted platform anyway on the basis of his support for the continuation of the war & permanent restoration of the Union, so not only would he probably consider a victory to be one for his repudiation of the platform as well, but what also has to be considered is that, by Election Day, most of the fighting in the South would've already been done anyway, & by the time he'd take office, the war would almost be over. Not only would Lincoln, Grant, & Congress - now knowing that they have a deadline - have probably just hastened their efforts to end the war & get the Confederates to surrender by March anyway, but if the war were to have still been ongoing by the time he took office, then McClellan could've easily garnered the necessary support to do the little that'd still need to be done.

Now, the more significant change that ought to be discussed is how a McClellan administration handles Reconstruction. Congress would've undoubtedly passed the 13th Amendment during their lame-duck session in order to put it to the states with the time that they still had, so there'd still be emancipated slaves to protect after the war, but the 14th - let alone the 15th - obviously aren't happening.

[Unconditional Surrender Truman]

Even the 1864 Copperhead-authored Democratic platform sought to restore the Union on the basis of "the federal union of the states,"

Indeed. While some Copperheads did doubtless favor "peace at any cost," most nationally prominent Peace Democrats proceeded under the delusional belief that the South would return to the Union of her own free will if a Democratic administration would repeal the Emancipation Proclamation and pass new guarantees of the continuation of slavery. This idea had no basis in reality, as Confederate papers were full of angry declarations that the South would never accept peace without independence, and was essentially the result of Northern Democrats swallowing their own pre-war propaganda, which blamed Republicans and abolitionists for provoking the South to secession by agitating on the slavery question.

Congress would've undoubtedly passed the 13th Amendment during their lame-duck session

I don't know about that. Bear in mind the newly-elected Congress didn't take their seats until December 1865, so Lincoln would still have had to contend with the outgoing Congress, in which the Republicans were a minority in the House. Without the votes of Democratic members who had been promised jobs in the Second Lincoln Administration in exchange for their support, the Thirteenth Amendment would not have passed IOTL. Many of those members had voted against ratification in 1864 and switched their votes only after they had lost re-election. In the event of a McClellan victory, (a) presumably many of those members would have won reelection, and (b) Lincoln would be in no position to offer government jobs in exchange for "yes" votes —so unless McClellan decides to take up the cause (unlikely), you're not going to see nationwide emancipation until 1869 or 1870 at the earliest.

[True Federalist (진정한 연방 주의자)]

For Lincoln to lose reelection, the war would have to have gone considerably worse for the Union than was the case in OTL. That means that President McClellan would not step into the White House on March 4 with the final defeat of the Confederacy imminent.