I insist? I don't do so alone:
"For three weeks the administration newspapers have been assuring us that Fort Sumter would be abandoned... Mr. Lincoln saw an opportunity to inaugurate civil war without appearing in the character of an aggressor" - April 13, 1861 Providence Daily Post
...this unarmed vessel... is a mere decoy to draw the first fire from the people of the South, which act by the pre-determination of the government is to be the pretext for letting loose the horrors of war." - April 12, 1861 Jersey City American Standard
Jefferson Davis appointed a number of peace commissioners, in conformity with a resolution of the Confederate Congress, whose mission was to travel to Washington, D.C., in March 1861, before the attack on Fort Sumter, and offer to pay for any Federal property on Southern soil as well as the Southern portion of the national debt. Lincoln refused to even see them or acknowledge their existence (like you!). Napoleon III offered to mediate the dispute, but Lincoln refused to meet him as well.
If you doubt Lincoln's aforethought, consider as well his letter to naval commander Gustavus Fox (May 1, 1861 - after the fact), "You and I both anticipated that the cause of the country would be advanced by making the attempt to provision Fort Sumter even if it should fail; and it is no small consolation now to feel that our anticipation us justified by the results."
Good. You don't negoiate with extortionists under any circumstances. And where exactly would the President of the United States gain constitutional permission to give away Federal property at any price. Since you're such a stickler on the Constitution, why don't you show us that clause that allows the President to give away land and property without congressional apporval. When did the confederates ever petition congress, or the courts, to gain permission to take that property? Unilateral secession, to paraphrase Madison, is nothing but revolution.
It was no damn accident that Jeff Davis waited till Congress was out of session before he initiated hostilities. He considered Lincoln to be some naive country rube who would freeze up in a crisis like Buchanan did. Lincoln didn't freeze. He instead preserved the last great hope mankind --- The United States of America.
Napoleon III offered to mediate the dispute...
ROTFLMAO. I'm sure Charic offered to "mediate" between Bush and Saddam too. Should we have taken that deal? The French are always the French. Are they your buddies?