Every July 4th, Americans gather at picnics, watch parades and shoot off fireworks to celebrate the birth of the United States. But some years are more notable than others. In 1826, Founding Fathers and former presidents John Adams and Thomas Jefferson marked the nation's 50th anniversary by dying on that same Fourth of July. In 1976, America enjoyed its bicentennial with, among other things, a five-story birthday cake in Philadelphia.
But of all 237 American birthdays, one stands out as the greatest of them all. On July 4th, 1863, just one day after the decimation of Pickett's Charge ensured defeat for Robert E. Lee at Gettysburg, the Confederate stronghold at Vicksburg, Mississippi finally surrendered to Union General U.S. Grant. While the Army of Northern Virginia would never again threaten Washington, the Confederacy was split in two as the Mississippi River became a Northern highway. Though two years of vicious fighting and hundreds of thousands of casualties were still to be endured, the Civil War had reached its turning point. On the 87th birthday of the United States, Americans could begin to believe, as President Lincoln would later explain, "that this nation, under God, shall have a new birth of freedom -- and that government of the people, by the people, for the people, shall not perish from the earth."

This week, all eyes have been focused on Gettysburg, Pennsylvania, where a quarter million visitors gathered to watch a massive reenactment of the three day battle that turned the tide of the war. The National Review and Esquire offered blow-by-blow accounts of the epic struggle when 85,000 Union troops and 65,000 Southerners fought, bled and died at places with names like Cemetery Ridge and Little Round Top. As George Will explained in the Washington Post, with Lee's defeat "a small crossroads town became the hinge of American, and hence world, history":

And in spite of Antietam, which repulsed the first invasion of the North, secession could still have succeeded if Robert E. Lee's second invasion had shattered Northern support for the war by smashing the Union army at Gettysburg.

Its import was not lost on the 150,000 men--51,000 of whom would be killed, wounded or captured--over the three days spanning July 1 and July 3, 1863. On the second day, the 262 men of the 1st Minnesota rushed to fill a gap in the Union line at Cemetery Ridge, charging 1,600 Confederates. Only 47 of the 1st emerged unhurt; the 82 percent casualty rate was the highest of any Union regiment in the entire war. As one survivor put it:

"Every man realized in an instant what that order meant--death or wounds to us all, the sacrifice of the regiment to gain a few minutes' time and save the position."

The position and, perhaps, the United States of America.

And yet, what became the decisive battle of the Civil War started almost by accident, as Lee's invading columns inadvertently encountered Union General George Meade's troops in the small college town.
The contrasts with the Vicksburg campaign in the West could not have been more striking. While Lee was doomed by a rare, almost suicidal frontal assault on Cemetery Ridge on July 3, it was Grant's unusually high risk strategy in the West that lead to the siege and fall of Vicksburg on the Fourth. And from the beginning of the conflict, the North saw the capture of Vicksburg as essential to winning the war. As President Lincoln himself explained:

"See what a lot of land these fellows hold, of which Vicksburg is the key! The war can never be brought to a close until that key is in our pocket...We can take all the northern ports of the Confederacy, and they can defy us from Vicksburg...I am acquainted with that region and know what I am talking about, and as valuable as New Orleans will be to us, Vicksburg will be more so."

Lt. Colonel Robert Bateman recently offered a primer as to why:

This is how you need to think about the Mississippi River. Not as a minor sidebar in your cross-country drive, or something seen out of the window at 35,000 feet, but as both the central vein and artery of just about everything and every community west of the Appalachian mountains. In other words, in 1863, most of the damned country.
Then, as now, the river was a major conduit for trade, the lifeblood of any nation's economy and strength. Before the war the river was the essential artery and vein (with trade flowing in and out) of the entire center of the country. Materials and goods from all of the Midwestern states, north and south, flowed down to New Orleans and then out across the planet.

Even after the daring Union naval assault in April 1862 that bypassed and later captured heavily fortified New Orleans, Vicksburg remained a Confederate choke point on east bank of the Mississippi. To position himself to take it, General Grant launched a risky campaign in March 1863, crossing the river north of the city and heading south along the west bank. Then crossing back to the east side of the Mississippi south of Vicksburg, Grant in May swung around to attack the city from the east. After repeated assaults were repulsed by Vicksburg's 35,000 defenders under CSA General John Pemberton, Grant laid siege to the city.
For almost two months, Vicksburg withstood the tightening Union noose. But with his troops and the townspeople on the brink of starvation, Pemberton recognized that surrender was the only course. And the Confederate General, originally from Pennsylvania, made clear his decision to lay down his arms on July 4th was no accident:

"I know their peculiar weakness and national vanity; I know we can get better terms from them on Fourth of July than on any other day of the year."

Pemberton was right. In a preview of Lee's surrender at Appomattox two years later, he got very generous terms from Ulysses S. Grant, which included the parole of his troops and allowing officers to maintain their side arms and horses. Nevertheless, Vicksburg did not celebrate the Fourth of July for the next 81 years.

The meaning of the fall of Vicksburg and Lee's devastating defeat was clear to all. "The Father of Waters," Lincoln said, "again goes unvexed to the sea." Back in Pennsylvania, Elisha Hunt Rhodes of the 2nd Rhode Island Infantry was joyous over "The Most Glorious Fourth." As Ken Burns recounted in The Civil War:

"July 4, 1863. Was ever the Nation's Birthday celebrated in such a way before?" Elisha Rhodes exulted in his diary. "I wonder what the South thinks of us Yankees now! I think Gettysburg will cure the Rebels of any desire to invade the North again.
Still more good news came the next day. "Glorious news!" Rhodes wrote. "We have news that Vicksburg has fallen! We have thousands of prisoners and they seem to be stupefied with the news."

Those captured Southerners were not alone. In Richmond, the Confederate chief of ordnance Josiah Gorgas understood what the twin Union victories meant:

"Events have succeeded one another with disastrous rapidity. One brief month ago we were apparently at the point of success. Lee was in Pennsylvania threatening Harrisburg and even Philadelphia. Vicksburg seemed to laugh at all of Grant's efforts to scorn. Now the picture is just as somber as it was bright then. It seems incredible that human power could effect such a change in so brief a space. Yesterday we rode on the pinnacle of success. Today absolute ruin seems to be our portion. The Confederacy totters to its destruction."

Gorgas' obituary was premature. July 4, 1863 wasn't the end of the Confederacy. But it was the beginning of the end. Even in the face of war-weariness in the North, after Gettysburg and Vicksburg the Union's industrial might and massive manpower advantage meant that victory in a war of attrition was likely now only a matter of time.
But that wasn't the only legacy bequeathed by July 4, 1863. As George Will (like Shelby Foote over twenty years earlier) explained, the romanticism of the South's "Lost Cause" would owe much of its strength to Pickett's heroic and hopeless charge in the battle of Gettysburg, a contest that came so close to going the other way:

In "Intruder in the Dust," William Faulkner famously invoked the tantalizing power of possibility:
"For every Southern boy fourteen years old, not once but whenever he wants it, there is the instant when it's still not yet two o'clock on that July afternoon in 1863, the brigades are in position behind the rail fence. . . . That moment doesn't need even a fourteen-year-old boy to think This time. Maybe this time with all this much to lose and all this much to gain: Pennsylvania, Maryland, the world, the golden dome of Washington itself."

Meanwhile, Grant's generosity and benevolence at Vicksburg would be repeated when he accepted Lee's capitulation in April 1865. As he later wrote of the scene at Appomattox:

"I felt sad and depressed at the downfall of a foe who had fought so long and valiantly, and had suffered so much for a cause, though their cause was, I believe, one of the worst for which a people ever fought."

As President, Ulysses Grant continued to offer not recriminations or retribution but respect for Southern sensibilities. In 1869, several Congressmen sought to add to the Capitol rotunda a huge mural depicting Lee surrendering to Grant at Appomattox. As authors Harold Holzer and Gabor Boritt wrote, Grant would have none of it. "He said he would never take part in producing a picture that commemorated a victory in which his own countrymen were losers." Grant is said to have remarked:

"No, gentlemen, it won't do. No power on earth will make me agree to your proposal. I will not humiliate General Lee or our Southern friends in depicting their humiliation and then celebrating the event in the nation's capitol."

As for Abraham Lincoln, he would pronounce the meaning of Gettysburg and that glorious Fourth in his immortal words dedicating the new national cemetery in November, 1863. Well before most of his countrymen would accept the cause of human liberty--and not just the preservation of the Union--as the purpose of the North's fight, Lincoln proclaimed:

Four score and seven years ago our fathers brought forth on this continent, a new nation, conceived in Liberty, and dedicated to the proposition that all men are created equal.
Now we are engaged in a great civil war, testing whether that nation, or any nation so conceived and dedicated, can long endure.

That test wasn't complete on July 4, 1863. But 150 years ago today, the answer--that the United States of America could and would endure--was finally becoming clear.