Historians, re-enactors and ordinary people all take a powerful interest in the four-year conflict over slaves, money and states¿ rights.
US Civil War: bloody conflict began 150n years ago
CHARLESTON, South Carolina // The message from Fort Sumter was polite but firm.
Major Robert Anderson, the Union commanding officer, refused to accept provisions for his hungry troops without paying for them, announced a courier, who had just stepped into the information office of the National Park Service on Fort Moultrie, a mile across the water on the mainland in South Carolina.
A man in a grey uniform received the courier with a curt nod, as two park rangers looked up from their computers.
Outside, on a grey and humid day, visitors in shorts and flip-flops, digital cameras hung from their necks, mingled with weary-looking uniformed men carrying muskets and sporting two-day stubble.
The troops were ragtag bunch, much like the volunteers and mercenaries who made up the Confederate forces assembled here outside the port city of Charleston would have appeared on this date 150 years ago.
But a fighting force that 1861 unit was, and today marks the 150th anniversary of the first battle of what would become the US Civil War.
The battle of Fort Sumter - better termed the Bombardment of Fort Sumter, according to historian Richard Hatcher of the National Parks Services - saw Confederate forces of the then seven seceding southern states lob 4,000 artillery rounds towards the island fort over 33 hours.
The soldiers there, representing the Union government, finally lowered the American flag and surrendered.
Only one Union soldier was killed in the fighting, and that due to a backfiring canon. The relative civility of the battle gave little indication of the bloodletting that would follow.
About 620,000 soldiers were killed during the four years the war would last. It was the most devastating conflict America has ever fought.
Only once the Vietnam War began to take its toll 100 years later did the combined number of American military casualties in every subsequent war exceed the number of those lost in the Civil War.
And the numbers remain in dispute. New research, said James McPherson, a Princeton University professor and a Civil War historian, suggests that the real number was actually higher than 700,000.
He attributes the discrepancy to lost or incomplete records and says the undercounting is largely on the Confederate side.
Indeed, two of the states that made up the 11-state Confederacy are today locked in a contest over which lost the most lives, with North Carolina now contesting Virginia's traditional claim to have lost the most soldiers during the war.
It is a "curious contest", said Mr McPherson, and one that indicates the lasting impact of the war on the whole American consciousness.
This is particularly true in the South, where he said many, though no longer a majority, are still trying to reconcile the sacrifices that were made "with the destruction of the way of life for which they fought, which was based on slavery".
"One way to do that is to identify with the Confederates as fighting a losing cause but a noble cause … and the more you lose, the nobler you appear."
Many of the hundreds of volunteers squatting in tents outside Fort Moultrie that for a full week will be re-enacting the events of 150 years ago would subscribe to the "noble cause" view of the Civil War, a term many of them also dispute.
"It was a War Between States," said Jeff Antley, one of the organisers of the re-enactment of the '150th Anniversary of the Firing on Fort Sumter', and a member of the Sons of Confederate Veterans, an organisation made up of the male descendants of Confederate fighters.
The group works to preserve the legacy and heritage of the "heroes of the Southern cause".
The Confederate states had seceded, Mr Antley said, and therefore, although all were Americans, properly defined this was not a civil war.
Nor was it primarily about slavery, he said, broaching the issue only reluctantly. At the outbreak of war, four million blacks were owned as slaves in southern states, most of them working as farm labourers. Slave property represented one of the greatest sources of wealth in the Confederate States.
Slavery, Mr Antley said, was "abhorrent" but had not been a moral issue then. At stake, he said, were states' rights and a growing disparity between the wealth of the industrialising North and the agrarian South due to a taxation system that weakened the latter.
The more than 270,000 visitors, mostly Americans, who came to Fort Sumter in 2010, attest to the continued resonance of the war in America, said Mr Hatcher, the park historian.
This anniversary year, the number will spike as will a "very intense" Civil War collectors' market, that exists across the US, he said, where an original uniform from Fort Sumter can cost as much as US$100,000 (Dh367,290).
He would not even venture a guess as to how much the original uniform worn by Major Anderson would fetch today. But for Mark Silas Tackitt, the man wearing the carefully reconstructed copy, playing the role of Fort Sumter's commander was a unique chance to "live history".
Mr Tackitt, like the 300 volunteers across the water, was living on the rations that would have been available to soldiers at the time, "grits, rice and pork". It showed, not least on the tired uniformed re-enactors propping themselves up against the remnants of the fort's brick walls.
But it was a sacrifice the Seattle lawyer said he was happy to make for the week to pursue what he called "The Hobby", as he dispatched his courier to Charleston to reject the free supplies they had offered his soldiers.