Historical What-Ifs with ChatGPT

Utilizing AI to simulate war games

Ever wondered what would happen if the 3rd Maine held the Peach Orchard at Gettysburg? I found out—thanks to a little AI-assisted what-if. ChatGPT is great for generating code, researching, learning a language, and revising writing. Sure, it has drawbacks, and sometimes it’s even flat-out wrong. But it’s still a fascinating resource. I’ve used it as a writing group, a lesson planner, and—most recently—for war gaming.

That’s right: I’ve prompted the chatbot to roleplay historical military leaders in text-based battle simulations. I tell it:

“Take on the role of the opposing side and his subordinates. Based on their personalities, temperaments, and command styles, react to my moves. Do not make things easy for me. Engage my forces as necessary and in the method most appropriate to the opposing commander’s role.”

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Why the Peach Orchard?

As a Maine-based Civil War reenactor, you might think I’d start with Little Round Top. If you knew me better, you’d know my real fascination lies with the 16th Maine, 3rd Maine, 17th Maine, and the Maine batteries. So I chose the 3rd Maine and the Peach Orchard as my first scenario.
My goal: see if a tactical change could reshape the battle—and maybe the war. What if Ward’s brigade, anchored by the 3rd Maine, managed to hold off Barksdale’s Mississippians and Wofford’s Georgians?

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Historical Reality

On July 2, 1863, Ward’s brigade faced Kershaw’s South Carolinians head-on. Kershaw hit hard, but the Federals pushed them back—briefly. Then Barksdale smashed in, overwhelming Ward’s position. The Peach Orchard fell, the Union flank collapsed, and Lee felt confident enough to launch what became Pickett’s Charge the next day.

My Setup

In my simulation, I repositioned Ward’s troops slightly differently. The 3rd Maine and 20th Indiana faced southwest, with an artillery battery intermingled. On the southern flank, the 86th New York and 99th Pennsylvania braced for Barksdale’s assault. The 124th New York sat in reserve.

Simulation #1: The “Too Cautious Meade” Scenario

In this alternate history, Ward held the orchard. Willard’s brigade arrived early to blunt Wofford’s attack. Together, they repelled Barksdale and even launched a limited counterattack, threatening Hood’s left and delaying his push on Little Round Top. By day’s end, Lee was rethinking a frontal attack.

Instead, he maneuvered toward Pipe Creek, Maryland—Meade’s historical fallback position—and used J.E.B. Stuart’s cavalry to screen the movement. The VI Corps, sent by Meade to investigate, got smashed by Longstreet and Ewell. Lee then moved toward Washington, D.C., prompting foreign statements of support for the Confederacy. Lincoln, in this version, concedes to a constitutional convention. The war “ends”… for now.

I called BS. “No way would Meade risk isolating a corps like that.” Time for a redo. Taking my request for “no pity,” ChatGPT played Meade much better. General Lee still disengaged from Gettysburg, shifting to Pipe Creek. With cavalry screening, he pivots toward Baltimore, striking the city’s supply stores and withdrawing quickly. Not willing to risk remaining in Maryland, Lee returns to Virginia, establishing a defensive line along the Rappahannock River. 

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Simulation #2: The “Better Meade” Scenario

General Ewell holds the left (West), Longstreet the center, and A.P. Hill the right (East). Stuart’s cavalry (Fitz Lee, Rooney Lee, and Wade Hampton) conducts raids, secures additional crossings, and harasses Union movement. Lee plans a fall invasion, having successfully rattled the North. However, the South is still hurt by the capture of Vicksburg by Ulysses Grant. 

Meade, pressured by President Lincoln and his administration, maneuvers to attack Lee in late August. One of the main crossings is at Beverly Ford. There, Rodes’ division from Ewell’s corps dug into the high ground. The position was similar enough to the Confederates who held off Federal attacks at Burnside’s Bridge during the battle of Antietam. Union attacks here are met with withering fire. 

In other areas, Confederate cavalry, operating aggressively along the river crossings, engaged elements of Buford’s Union troopers. In a sharp series of running fights, the Confederates managed to capture a number of prisoners and—most notably— a few hundred of the new Spencer repeating carbines. These were quickly redistributed among elite mounted detachments, giving them a short-term firepower boost well out of proportion to their numbers.

When a Federal force attempted to push across at Kelly’s Ford, A.P. Hill’s corps rushed to met them with determined resistance. The engagement was brief but punishing. Confederate volleys and artillery fire staggered the Union advance before it could properly deploy. Hill chose not to overextend, breaking contact and pulling back to his prepared fallback line, leaving the Federals with nothing to show but heavy casualties. Hill and Ewell crossed the Rappahannock as if to move on Washington. Worried about another raid, Meade moves most of his corps to block the Confederates. Hancock’s II Corps remains to cover Longstreet.

Under the cover of darkness, Longstreet ordered Pickett to flank II Corps left flank and Hood on the right. Pickett probed in the morning, requiring a shifting of Yankee brigades. With a weakened flank, Hood attacked. Once Hancock realized Longstreet’s intentions (or what he thought they were), he moved brigades to the right. McLaws’ division joined in, and Pickett’s probe became a full-on assault. Longstreet’s infantry shattered multiple Union brigades and rolled up part of Hancock’s flank. In the ensuing collapse, roughly 5,000 Federal soldiers were taken prisoner along with guns, colors, and supplies. The victory was decisive enough to leave Hancock’s corps combat-ineffective for the immediate campaign.

With Federal forces in disarray, Ewell’s Second Corps and elements of Hill’s command advanced toward the defenses of Washington, D.C. They probed outer picket lines and skirmished near the capital’s outer works, sowing alarm in the city. However, Lee judged that a frontal assault on the fortifications would be too costly, especially with Meade’s army regrouping. The Confederates instead adopted a menacing posture—keeping pressure on Meade, tying down Federal troops in the capital’s defense, and then slipping back across the Potomac in good order. The army eventually withdraws into Virginia, maintaining the initiative and avoiding a major defeat.

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Takeaways

As far-fetched as surviving a gutshot, the first version didn’t feel plausible. The second? Still alternate history, but more believable. ChatGPT has its quirks, but if you keep it honest, it can run a surprisingly convincing campaign.

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Your Turn

Civil War buffs—how plausible is this? Would Meade or Lee act this way? What about the ripple effects of a raid on Baltimore? And if Lincoln got fed up, who might replace Meade—Hancock?

Suggest another simulation: What if D-Day failed? What if Berlin was taken entirely by the Soviets? What if Rome lasted into the 1200s?

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Second Pass members: you’ll get a period-style report from Lee to Secretary of War Seddon, plus the raw chat transcripts from the Peach Orchard simulation and its follow-up campaign. Not a member? Consider joining to get the monthly newsletter and extras like this.