In the aftermath of the Battle of Antietam, Union President Abraham Lincoln urged his commanders and battle-hardened veterans to remain resolute and to pursue and finish off the enemy. He believed the war was God's work and told his commanders it was essential they seize the initiative.
As it was, despite President Lincoln's appeal, the war dragged on for three more years.
Today, with Americans across the country celebrating Independence Day and reflecting on the freedoms they enjoy, another war president had been urging his citizens to dampen their growing anxieties and remain resolute in the face of the ongoing conflict in Iraq.
With more than 1,700 US troops and perhaps more than 100,000 Iraqi civilians having been killed since the invasion in the spring of 2003, George Bush last week stood in front of an audience of uniformed soldiers and declared that "the proper response is not retreat". He, too, believes he is an instrument of God.
"Like most Americans, I see the images of violence and bloodshed," he said during the 28-minute speech televised to the nation. "Every picture is horrifying and the suffering is real. Amid all this violence I know Americans ask the question 'Is the sacrifice worth it?' It is worth it and it is vital to the security of our country.
"This Fourth of July, I ask you to find a way to thank the men and women defending our freedom by flying the flag. At this time when we celebrate our freedom, let us stand with the men and women who defend us all."
The President's speech at Fort Bragg, North Carolina, tapping directly into the patriotism of 4 July as well as the nation's general support for its troops, was specifically designed to try to quell growing concern about the course of the conflict in Iraq and his role in it. A total of 56 per cent - a record high - now disapprove of Mr Bush's personal handling of the situation in Iraq. Also, for the first time, a narrow majority - 52 per cent of those asked - said they believe the administration misled the country before the invasion about the threat posed by Saddam Hussein and his alleged arsenal of (non-existent) WMD.
And yet those same polls also reveal a certain grim resolution and determination that President Lincoln might have hoped for in the aftermath of the terrible battle for America's future that was fought on these hillsides fewer than 150 years ago. Even among those who were opposed to the war, there remains a belief among many that America must "see it through".
Although 37 per cent of people think the President should order an immediate withdrawal of troops, more than 60 per cent say US forces must stay in Iraq until the situation has been stabilised and Iraq's security forces are sufficiently prepared.
The timing of Mr Bush's speech and the imagery in which he wrapped himself last week was, as ever, perfectly stage-managed. The national holiday of 4 July has traditionally been a time for festivities and fireworks, of marching bands and the volunteer fire brigade, of hot-dogs and home-made ice cream eaten on Main Street. It has been a time for communities to come together and to collectively hoist the Stars and Stripes in a no-strings-attached display of wholesome patriotism.
Yet since the attacks of 11 September, 4 July has become a more reflective day. It remains a time for celebration, but it has also become a time for consideration. By again seeking to link the Iraq war to the events of 11 September - a link that has repeatedly been shown not to exist - Mr Bush was able to claim the present conflict is the price America has to pay to celebrate today. For many, it was an argument that worked.
"It's not a party day," said Charles Marvill, 56, a Vietnam veteran whose remarkable wooden home in a quiet Sharpsburg street was used as a field hospital for the dead and the wounded of Antietam. "It is a time for celebration but it is a time to celebrate what we have and what we have been provided with. As for President Bush, there are a lot of people from the other side of the spectrum to me - the Democrats and the Liberals - complaining because he will not give a pulling-out time. The worst thing that anyone could do is give away our war strategy. We are not going to let the enemy know what we are going to do."
America's military veterans are uniquely placed to offer a perspective on the conflict in Iraq. With many having served in combat and aware of the personal cost that sometimes comes with such a vocation, they are also sometimes suspicious of the motives of civilian leaders who send the troops into battle.
Vernon Cassell, who served as an military policeman in Germany in the early 1960s and whose job was often to courier information relating to the US nuclear arsenal, is one such veteran who had his doubts about Mr Bush.
Sitting at the circular bar of the American Veterans Club in the town of Middletown, fewer than 10 miles from Sharpsburg, Mr Cassell, 65, said: "I think it was probably unnecessary. I think there were other ways of dealing with Saddam, like we did during the Cold War. Stay back and put pressure on. I'm a Republican but I am very disappointed with the President and the way things are going."
In a small town such as Middletown, with a population of fewer than 3,000, the community of veterans is particularly close. Many get their hair cut at the barber shop on Main Street, owned by Larry Bussard, himself a Cold War army veteran. His barber shop stands next to the Zion Lutheran church with its tall, white steeple and a plaque which notes that it also served as a field hospital during Antietam, and the Battle of South Mountain. Mr Bussard, 59, said most of the veterans he knew believed, like him, the US needed to finish its task in Iraq quickly then leave.
"I have heard a lot of them say, 'If we are going to do this, let's get on and do it and get out'. I grew up during the Vietnam era and it went on and on. You don't want this going on and on and with all these youngsters getting killed." Another veteran drinking at the clubhouse, William Fox, who served in Vietnam with the 1st Air Cavalry between 1968-69, could also see the parallels.
"Obviously that was jungle and this is more urban but it's the same sort of enemy" said Mr Fox, a postal worker who said he followed the news from Iraq and Afghanistan every night on television. "We screwed it up from the get-go. We never had enough troops. A country with 25 million people and we had 140,000 troops? It was never enough. I think someone underestimated."
But Mr Fox said he read Mr Bush's comments from Fort Bragg and was in general agreement. It was not the time, he said, to cut and run. "I agree with Bush and the idea that we have to stand tough. I hope we can get the sides together and work out their differences. It needs a political solution. People have to sit down and say, 'This is for the good of the country'. Common sense needs to prevail."
Like so many communities in the American heartland, Middletown has lost many of its sons to battle. A war memorial next to the park where the town was holding its 4 July celebration listed the names of about 60 local men who had been killed in the First and Second World Wars.
Outside the veterans' club was a separate memorial to James Caniford, who joined the US Air Force after leaving Middletown high school in 1966. His AC-130 plane was shot down over Laos in 1971 and his body was never recovered. He is listed by the Pentagon as "Unaccounted for in South-east Asia".
Another veteran, Robert Haupt, saw many comrades die and lost several friends and relatives during the Second World War. Now 80, he served three years in the Navy in the Pacific as a driver of amphibious craft whose task was to drop off the infantrymen and marines on the beaches during assaults.
Sitting on his veranda of his home in Middletown, still living on the same street in which he was born, he rattled off a list of friends who had never returned from war. He had been lucky. There were no terrorists in his day, he said, things were more straightforward. He supported Mr Bush's decision to invade Iraq but was concerned about the way things are going.
"I think he was doing his best to help people," he said, as the day's heat started to cool. "I voted for him, but I don't know how we are going to get out. I supported the war though it turned out differently than what we thought about WMD."
All of these men, all of the veterans across the country, need little reminder of the costs of war. Yet should they need it, here there is that constant reminder from an earlier age, attracting visitors from across the nation and holding its own 4 July celebration.
Few who visit the site of the Battle of Antietam - or indeed the Battle of Gettysburg, an hour's miles away - forget the experience of the brooding woods and field where so many Americans lost their lives.
A month after Antietam, one of its veterans, Dr William Child, a Union surgeon with the New Hampshire Infantry, had these words for posterity in a letter to his wife: "When I think of the Battle of Antietam, it seems so strange. Who permits it? To see or feel that a power is in existence that can and will hurl masses of men against each other in deadly conflict. Slaying each other by the thousands, mangling and deforming their fellow men, it is almost impossible. But it is so, and why, I cannot know."Reuse content