Maybe, tomorrow will dawn misty and autumnal over those timeless, softly rolling pastures of west-central Maryland by Antietam Creek, just as it did 150 years ago.
The name, which is pronounced "An-tee-tum", derives from an old Algonquian Indian word meaning "swift water". But on 17 September 1862, in those same pastures and croplands, blood ran as copiously as water, in the deadliest single day in all American military history.
Today, like every other major battlefield of the US Civil War, Antietam is cherished and meticulously tended, studded with monuments to the units that fought there, crisscrossed by the zigzagging split-rail fences that farmers have used in these parts for centuries, and that, in the war, provided ready firewood for the troops.
For all the reminders, it's hard to imagine a charnel house in so bucolic a setting. Yet, between them, Union and Confederate forces suffered 23,000 casualties, of whom at least 3,600 were killed. "The air was full of shot and shell … it seemed almost impossible for a rat to live in such a place," the Confederate soldier J M Polk, of the 4th Texas Infantry, wrote of what is now known simply as "the Cornfield", where the bloodiest fighting of the bloodiest battle unfolded.
It can be argued that Antietam was a modest affair when compared with some other 24-hour killing fields: the first day of the Battle of the Somme on 1 July 1916, for instance, when British losses totalled some 57,000, including 19,240 killed ("This cannot be considered severe in view of the numbers engaged," wrote General Douglas Haig in his diary afterwards); or Napoleon's Pyrrhic victory at Borodino on 7 September 1812, which cost him one third of the 150,000-strong Grande Armée, killed or wounded.
Antietam pales too beside the most murderous day on British soil. It happened near the Yorkshire village of Towton on 29 March 1461 during the War of the Roses, when – if chroniclers of the age are to be believed – 28,000 men, most of them Lancastrians, perished. If true, that represented a staggering 1 per cent of the English population, wiped out in 24 hours.
And even within the limited context of the American Civil War, Antietam is easily overlooked. It is not a bookend like the Confederate shelling in April 1861 of Fort Sumter, South Carolina, that started the whole thing, or Sherman's devastating campaign "from Atlanta to the Sea" in the last weeks of 1864 that finally broke the South's resistance.
And it was less immediate than the Battle of Bull Run on 21 July 1861, the first major clash of the war when, armed with opera glasses, the great and good of Washington made the 20-mile trip west to follow the action. Expecting an easy Union victory, they witnessed a powerful Confederate counter-attack and a panicky Union retreat that for a moment seemed to throw open the gates of the federal capital to the invader. That did not come to pass. But Bull Run served notice that the conflict would be a lot tougher than anyone imagined.
Nor was Antietam marked by any brilliance of the sort that Robert E Lee showed in the spring of 1863 at Chancellorsville, where he secured the greatest Confederate victory of the war (but one that also brought the death of his ablest commander, General Thomas "Stonewall" Jackson). Nor, unlike Gettysburg, is it perceived as a watershed – not least because it lacks the immortality conferred on Gettysburg by Lincoln's address four months afterwards, surely the most perfect 270-word speech ever uttered. Yet, whether measured by bloodshed or consequences, Antietam was a turning point to match any of the above.
In many ways the American Civil War prefigured the First World War, as old-fashioned tactics, cavalry charges and the like, ran into modern weaponry such as the Gatling gun, the forerunner of the machine gun used for the first time in 1862. That was what happened at Antietam. Thus the vast four-year toll of a war that historians last year revised upwards, on the basis of the 1860 and 1870 US census returns, to 750,000, out of a national population of roughly 35 million. Sherman's scorched-earth strategy meanwhile gave an ominous foretaste of the "total wars" of the 20th century.
Antietam also brought home to everyman the horrific reality of war. The first ever war photos, produced in travelling dark rooms, were taken at Antietam by photographers from the studio of Mathew Brady, the son of Irish immigrants, who in October 1862 opened an exhibition in New York called "The Dead of Antietam". Instead of "artists' impressions", Americans saw what the corpse-strewn aftermath of a battle actually looked like.
Another of Brady's subjects was Clara Barton, founder of the American Red Cross. After darkness fell on that long ago 17 September, she scoured the Antietam fields with a lantern, listening for the groans of the wounded, seeking out soldiers who otherwise would have been left to die.
The result of the battle itself? A draw. Historians reckon that the Union forces, twice as numerous, could have routed Lee had George McClellan, the commander whom Lincoln sacked soon after, been more aggressive. But it was Lee who most needed the victory, to carry the war into the Union heartlands. Ten months later he tried again at Gettysburg. There too he managed only another draw that amounted to a strategic defeat.
Most important, Antietam gave Lincoln the chance to transform perceptions of the war. Five days later, with the South repulsed, he issued a preliminary Emancipation Proclamation. No longer was it a mercantile conflict, but a great moral struggle over slavery. That in turn probably kept Britain, so reliant on Southern cotton for its textile industry, from giving an international buttress to the Confederate cause. One way and another, Antietam Creek and 17 September 1862 are a place and a date to remember.