[DiogenesLamp]

But Lincoln's final orders, as we have reviewed before, said exactly what he told SC Governor Pickens -- no use of force or reinforcement if no Confederate resistance.

But therein lies the rub. The Confederates had been sieging Ft. Sumter for something like 3 months with the stated position that the Union contingent must leave.

To then back down under the threat of attack is an idea that no one would have accepted at the time. Both sides understood that allowing them to provision Sumter peacefully was not going to happen. Lincoln knew this before he sent the fleet. He was counting on it. They would have actually outsmarted him had they just allowed this to happen.

Given what both sides understood about the situation, the orders were effectively an attack order for the Union fleet to sweep away the Confederates seiging the fort.

The only problem was, the fleet didn't attack as everyone believed it would. Lincoln had used secret orders to send their biggest gunship on a wild goose chase to Florida, all the while hiding from it's sister ships in the Union and Confederate observers who would relay information of it's whereabouts if they identified it.

Clever trick that. He told the Confederates he was going to attack, and then didn't.

[BroJoeK]

DiogenesLamp: "But therein lies the rub.
The Confederates had been sieging Ft. Sumter for something like 3 months with the stated position that the Union contingent must leave."

Exactly, and even before Lincoln's inauguration, Jefferson Davis ordered preparations for military assault on Fort Sumter.
So as he announced in February, 1861, Davis intended to start war if "...the integrity of our territory and jurisdiction be assailed, it will but remain for us with firm resolve to appeal to arms...".
But Lincoln's message to Governor Pickens saying he would not "assail" didn't deter Davis.
Davis decided based on other sources (spies) that he was being "assailed" and so started Civil War, just as promised.

The fact is Davis's act of demanding Union surrender was itself a provocation of war and when his military assault followed, the fact of war was firmly established.
Lincoln's only issue was whether to accept Davis's war, and for that Lincoln was prepared.

Remember, in his March 4 inaugural Lincoln promised:

"The power confided to me will be used to hold, occupy, and possess the property and places belonging to the government, and to collect the duties and imposts; but beyond what may be necessary for these objects, there will be no invasion -- no using of force..."

"...In your hands, my dissatisfied fellow countrymen, and not in mine, is the momentous issue of civil war.
The government will not assail you.
You can have no conflict without being yourselves the aggressors."

And so it began.