Perhaps no war in 1861. But war would have come nonetheless. An independent Confederacy did nothing to change the overwhelming economic and social pressures on the slaveocracy for territorial expansion.
We could not be half-slave and half free. Over time we had to be all one thing or all of the other.
But I find it interesting that in 1861, you would have allowed an illegitimate insurrection to violate the territorial integrity of the nation. If I were on your Senate jury, I would surely find that you were guilty of gross malfeasance of office, dereliction of duty, and would have voted for your impeachment.
If say California, New Mexico and Arizona unilaterally formed a Confederacy today, siezed Federal Property, and fired on Federal facilities, would you allow them to go instead of fighting?
"Firing on that fort will inagurate a civil war greater than any the world has yet seen...At this time it is suicide, murder, and will lose us every friend in the North...You will wantonly strike a hornet's nest which extends from mountains to ocean, and legions now quiet will swarm out and sting us to death. It is unnecessary; it put us in the wrong; it is fatal." -- Robert Toombs, April 1861
If you had been the other 'president' would you have followed Toombs's advice? And there would have been no war, either.
That is an interesting comment.
IIRC Secretary of State Seward also wanted to gin up a conflict with Great Britain as a means of preserving the Union. So by following Seward's advice there would have been a war, just not a civil war.