Supreme court says this is when the war started; April 19, 1861
The confederates were apparently late. Lincoln had already been making war on them by the time they declared.
You know better than that.
Constitutionally, the U.S. Supreme Court does not declare war, and didn't in this case.
The ruling itself says war can be said to have started on different dates in different places, and merely for purposes of compensation in a civil suit chose the date of Lincoln's blockade announcement.
In fact, for months before that date Confederates had repeatedly provoked war, and started war at Fort Sumter.
As we have now repeatedly reviewed, a major military action attacking a country's military forces, such as Fort Sumter, is an act of war, period.
Union troops died in that action and were forced to surrender.
Any serious student knows that's the actual start of war, as surely as were Pearl Harbor and 9/11/01.
By contrast, Lincoln's response in calling for troops and a blockade were mere announcements, no battles were fought on that date, no Confederate soldiers killed.
Indeed, the first Confederate soldier killed in battle did not happen until June 10, six weeks later.
That was the true start of the Union's war, but by then Confederates had already been fighting for months with little to no Northern military response.
Of course you know all that, because you've been told it now many times.
So truth doesn't matter a whit to DiogenesLamp, does it?
Not really. As Chief Justice Chase said in his decision, "Acts of hostility by the insurgents occurred at periods so various, and of such different degrees of importance, and in parts of the country so remote from each other, both at the commencement and the close of the late civil war, that it would be difficult, if not impossible, to say on what precise day it began or terminated. It is necessary, therefore, to refer to some public act of the political departments of the government to fix the dates, and, for obvious reasons, those of the executive department which may be and in fact was, at the commencement of hostilities, obliged to act during the recess of Congress, must be taken...The proclamation of intended blockade by the President may therefore be assumed as marking the first of these dates, and the proclamation that the war had closed as marking the second."
April 19th was arrived at for legal reasons, and not because that marks the first act of the war. Your argument makes as much sense as saying that for the U.S. the Second World War began on December 8th since that was the day of the formal declaration rather than on December 7th, the day of the Japanese attack.