[Mark in the Old South]

No I do not think that would have ended the war. I believe subjection of the South was the goal long before the war started. I do not think the South would have required capitulation of the North even if that was possible but I do believe the North could have been worn down. My "what if" not only would have provided the South with many more fighting men. Still but not as much as some think, remember they were having enough trouble feeding the ones they had. And someone would still need to work the fields or all would starve.

The real value would have been the result in European Capitals. The biggest obstacle to international recognition would have been removed, popular support was already with the South and obtaining loans and supplies would have been easier. One more event like the Trent affair and England would have moved on the South's behalf. But none of that happened because slave owners did not want it and as a result they lost everything.

[norton]

If I said capitulation, I meant defeat; and the Lincoln government could have been defeated leading up to a cessation of conflict, negotiated separation, and an eventual end to slavery in both countries.

You're right, slavery was an issue in Europe but europeans have never been shy about jumping in bed with a winner.

I'm not privy to any debates or works that get into the deliberations of a slave holder's bloc. However:
The middle of a war is not a good time to simply disassemble the institution that maintains your coffers, and
Since there were a good number of black freemen already in the South I think that inducting slaves as well as black non-slaves with a promise of freedom/citizenship would have been practical and quite possible. I expect that Lee, not a fan of the institution, had the latter in mind.