What happens when an irresistible force meets an unmovable object? In Gettysburg, Pennsylvania 150 years ago, 51,000 people died or were severely wounded.

I’m in Gettysburg now, soaking in the historical moment with Civil War buffs, reenactors, curious locals, traveling families, bikers, historians, writers, artists, unidentifiable visitors from North and South. Everyone is friendly — happy, even, which is strange when you consider the disaster we are here to remember. The only way to know which of the two sides any person might feel they represent is to look at the license plates on their cars.

As I stood yesterday at the legendary copse of trees at the famous Angle on Cemetery Ridge with two of my kids, a blond biker dude with his girlfriend proudly announced to us that he had brought his horse with him today, though the horse was currently nowhere in sight. “You’re in the cavalry?” I asked him. He solemnly affirmed. Union? I wondered. Confederate? It didn’t matter. The fight was over. All that remains is our collective desire as a people to see through the gauze of history and understand what once happened on this field.

The Battle of Gettysburg was the physical climax of the Civil War; the Confederates would fight on for two more grisly years after their defeat here, but they would never attack again as they attacked at this spot. From the beginning of the war, they’d always held the weaker position. They had fewer resources, fewer soldiers, no international support. But the South was itself politically united to a degree the North was not, and the brilliant Confederate military chief Robert E. Lee’s main objective was political rather than military.

By invading the North through Maryland and Pennsylvania and winning battlefield victories, Lee hoped to break the Union’s political will to continue the fight. For the first two years of the war, Lee’s Army of Northern Virginia won one stunning victory after another on Southern territory — Manassas, the Peninsula, Manassas again, Fredericksburg, Chancellorsville. But Lee’s first attempt to invade the North and hurt the Union where it lived failed in Sharpsburg, Maryland near Antietam Creek in 1862. Gettysburg was the culmination of his second and last attempt.

A strange thought occurred to me as I strolled the dramatic terrain of Little Round Top and Devil’s Den with my family yesterday — a thought so bizarre that I didn’t bother mentioning it to anyone nearby. I’m sure I would have been scoffed at, but I think the strange thought is true: the most quintessential conflict in the Battle of Gettysburg was not between Confederate leader Robert E. Lee and Union leader George Meade (a capable but dull historical non-entity who would soon be replaced by Ulysses S. Grant). The real battle was between Robert E. Lee and his most trusted lieutenant, James Longstreet, who famously advised against Lee’s aggressive plan to attack the Union army directly.

Longstreet, no less brilliant a tactician and student of war theory than his leader and close friend Lee, yearned to always cling to the strength of the defensive position, and abhorred the terrible losses typically sustained by a moving attack against a stationary enemy. This is basic military science — as anybody who plays the board game Risk knows, you lose more by attacking than you do by defending. 150 years ago on this very morning, on the very spot where I now sit typing in a comfortable hotel room, Lee and Longstreet debated what to do with the modest victory they had achieved against the dug-in Union position on the hills beneath the town of Gettysburg on the first day of battle.

Both men’s opinions were extremely clear, and could not be reconciled. Lee wanted to attack with full strength. Longstreet wanted to sneak the army around the Union position and get between Meade and his command structure in Washington DC. This, Longstreet hoped, would force Meade to attack the Confederates, requiring the Union to sustain the heavy losses of an offensive assault against an entrenched position.

Lee and Longstreet debated this question, history tells us, in an extreme and emotional conversation on the morning of July 2, 1863. Lee would overrule Longstreet’s objections and order his full army to attack at Cemetery Hill, Culp’s Hill, the Bloody Wheatfield, the Peach Orchard, Little Round Top, Devil’s Den. The second day of battle would not go well for the Confederates.

On the night of July 2 and the morning of July 3, Lee and Longstreet would conduct the same debate again. Once again, Longstreet would urge Lee to sneak the Army south and wait for a Union attack. Once again, Lee would overrule his most trusted advisor and order Longstreet’s divisions to execute a frontal assault on the Union’s strong position. The single climactic infantry march of July 3, remembered today as PIckett’s Charge, would also go badly for the Confederates, and the three-day Battle of Gettysburg would end here.

One wonders how short the entire US Civil War might have been without the tactical brilliance of both Robert E. Lee and James Longstreet — who were, respectively, an engineer and a poker player. I mention this with some selfish regard because I personally relate to both of these intellectual backgrounds; I am also an engineer (a software engineer, while Robert E. Lee gained his expertise in the Army Corps of Engineers) and I am also a serious poker player (though I play Hold ‘Em, while I believe James Longstreet played Seven Card Stud and Five Card Draw, as well as Brag, a poker variant that isn’t played much anymore).

There can be no doubt that Robert E. Lee’s brilliant analytic skill and constructive familiarity with technology and logistics significantly extended the Confederate’s chances during the entire war. It’s not as clear how James Longstreet’s famed poker skills helped the South, but there is a significant moment in Michael Shaara’s Gettysburg novel The Killer Angels in which somebody asks Longstreet when it is appropriate to play an inside straight draw.

“Never,” Longstreet says. The person asks again, and Longstreet repeats his simple answer. “Never.”

In poker terms, of course, Longstreet is right. You can perhaps bluff an inside straight draw, but you must understand that this is a pure bluff. An inside straight draw is a very weak hand.

By attacking the well-entrenched Union position across Cemetery Ridge on July 2 and July 3 in Gettysburg, Robert E. Lee was going all-in on an inside straight draw. Gutshot, as they say. Longstreet saw it and hated it.

Pondering this 150 years later, I briefly wondered if the difference between Lee and Longstreet could be characterized as the difference between the mind of an engineer and the mind of a poker player.

After more careful pondering, I decided the poker player vs. engineer idea is probably a false path. Attacking the Union’s stationary position with moving force was bad poker and bad engineering. The essence of the debate between Longstreet and Lee before each attack must be found elsewhere. It is perhaps most accurate to guess that Lee had simply lost his mind on the morning of July 2, when he made the decision to attack.

To say that Lee was under a lot of stress at this point is, of course, an understatement. In poker terms, it appears that he was “on tilt”. In engineering terms, it’s clear that Lee badly needed a vacation before he made any more big decisions — and he wasn’t going to get one.

Longstreet saw the disaster play out in slow motion before his eyes, and tried hard to stop it from happening. He could not. Through the fuzzy gauze of time, various historians have either blamed Lee for disregarding his smartest field general’s good advice, or have blamed Longstreet for arrogantly pestering his commander with pessimistic questions when his commander only needed his enthusiastic support and fast, decisive leadership on the field.

The Killer Angels by Michael Shaara is an example of a Civil War book that treats Longstreet with admiration. Douglas Southall Freeman’s essential early biography Lee is an example of a history that disparages Longstreet without mercy.

Years after the South’s defeat in the Civil War, a famous incident occurred. A great reunion of Rebel soldiers was arranged, and James Longstreet was pointedly not invited — punishment, of course, for his perceived disloyalty to Lee and the alleged damage caused by his reluctance to shut up and do what he was told on July 2 and 3, 1863.

Longstreet didn’t feel he needed an invitation to this reunion, and showed up anyway. It’s said that the old man received a spontaneous standing ovation from the soldiers when he entered the room.

This is the morning of July 2, 2013. I’m writing this blog post from a Marriot Courtyard north of the field, where a hotel breakfast soon awaits me. I tried to find salt pork and hardtack to eat yesterday, but we ended up going to Ruby Tuesday’s instead. I’ll be reporting from the battlefield again after this day.

Thanks to Caryn for the photo at the top of the page.