I believe it was Alexander Stephens who helped popularize the name, "War between the states."
But as the loyal Union men definitely took their orders from Washington, that doesn't seem a very apt name.
Walt
"The Congress' official records are called or contain the name, "war of the rebellion."
Which we all know is hogwash because it was a war to test the legality of secession. Lincoln was wrong ... period!
'And seventy-two years before, Edmund Pendelton and James Madison had openly conceded the right of a State to secede from the Union, and the Virginia Convention of 1788 had expressly ordained that the right of secession was reserved to each State. This invaluable constitutional right, far from being a rope of sand, had on repeated occasions been used as an instrument of reconciliation among the several States, and had brought strength to the Union.'
Here are some speeches by President James Buchanan ... Lincoln's predecessor!
" The question fairly stated is, Has the Constitution delegated to Congress the power to coerce a State into submission, which is attempting to withdraw or has actually withdrawn from the Confederacy (meaning Union of States)? If answered in the affirmative, it must be on the principle that the power has been conferred upon Congress to declare war and make war against a State. After much serious reflection I have arrived at the conclusion that no such power has been delegated to Congress, or to any other department of the Federal Government. It is manifest upon an inspection of the Constitution that this is not among the specific and enumerated powers granted to Congress, and it is equally apparent that its exercise is not necessary and proper for carrying into execution any one of these powers. So far from this power having been delegated to Congress, it was expressely refused by the Convention which framed the Constitution."
'It is an historical fact that, on two occasions during their deliberations, the framers in the Philadelphia Convention voted to deny Congress the power of calling forth the military forces of the Union to compel obedience of a State, and on two further occasions they voted to deny Congress the power of sending the Federal army or navy into the territory of any State, except, as allowed in Article IV, Section 4 of the United States Constitution, - to repel a foreign invasion or at the request of its legislature or government to deal with domestic violence.
And for your further edification -
'Of the supposed power to use force of arms against secession, He (Buchanan) stated to Congress,
"But if we possessed this power, would it be wise to exercise it in existing circumstances? The object would doubtless be to preserve the Union. War would not only present the most effectual means of destroying it, but would vanish all hope of its peaceable reconstruction. Besides, in the fraternal conflict a vast amount of blood and treasure would be expended, rendering future reconciliation between the States impossible. In the meantime, who can foretell what would be the sufferings and privations of the people during its existence?"
"The fact is that our Union rests upon public opinion, and can never be cemented by the blood of its citizens shed in civil war. If it cannot live in the affections of the people, it must one day perish. Congress possesses many means of preserving it by conciliation, but the sword was not placed in their hand to preserve it by force." - 'A Constitutional History of Secession' - John Remington Graham