If Lincoln had withdrawn U.S. troops from that fort, he would have caved into blackmail and should have been impeached for dereliction of Presidental duties.
Individuals or mobs of citizens from any state never have a right to attack U.S. troops, never mind attack a United States military instillation.
Such actions are treason, sedition, and if such actions were undertaken today, it would naturally be termed a terrorist attack, plus being swiftly dealt with. Think about the same incident in 2005.
I fault President James Buchanan when he refused to act when a federal supply ship was attacked in Charleston Harbor in January 1861. Buchanan non-action set in motion the attack on Fort Sumter. Once again how would President Bush react if either whacked out leftists or Islamic thugs attacked any U.S. ship?
Are you aware Congress was not in session when Ft. Sumter was attacked & Lincoln took the required legal steps he knew were necessary to preserve the Union, because inaction, as demonstrated by President Buchanan, would have promoted further attacks by mobs of South Carolina, radical secessionists.
The fact is this: You can't compare actions of a group of states, to terrorist actions. The Confederacy seceded through what most people at the time felt were legal means.
They sent commissioners to NEGOTIATE a transfer of federal property. They were snubbed. Lincoln chose to initiate the actions that followed. The South had no choice BUT to fire on the fort, and force the troops out, or their sovereignety as a nation would have been a sham........
Lincoln was quite aware of the actions that would take place. He knew that when Southrons fired on the old flag, it would inflame passions. He was a consommate politician.