Reenactors at Gettysburg. (Matt McClain/ The Washington Post) Reenactors at Gettysburg. (Matt McClain/ The Washington Post)

Gettysburg, Pa. — Here, today, it’s expected to thunderstorm.

150 years ago the only storm was from the cannon fire. Little things like this make a vast difference in the tides of battle. Crecy was won because the English had dry longbows and the French did not. When it rains, some plans fall through and others coalesce.

The first day of battle at Gettysburg had concluded with the Union troops still in possession of the high ground along Cemetery Ridge, thanks to a series of fortuitously timed reinforcements. Union General Joshua Reynolds (who died fairly shortly after sending the message) announced that he would fight the enemy “inch by inch,” and his troops did so.

Confederate General “Baldy” Ewell had been given discretionary orders to take the high ground if possible. After a day of heavy fighting, including a few breakthroughs, he decided it was not possible. This bothered a brigade commander named Ike Trimble who had just gotten back from a wound and was hanging around Ewell’s headquarters. As reported in “Robert E. Lee: A Biography” in an exchange taken from the Southern Historical Society papers, he said, “Give me a division, and I will engage to take that hill.” “Give me a brigade, and I will do it! Give me a good regiment and I will engage to take that hill.” He got nowhere.

The failure to move against the Union position was another one of those decisions that would bear bad fruit for the Confederacy in the next few days, and, like other decisions that turn out to be pivotal in retrospect, suddenly there pop up lots of accounts afterwards from people who Knew How Bad It Was Going to Be And Said So at the Time. (This always happens, like when your neighbor turns out to be an ax murderer. “He seemed quiet,” you say. “Quiet, but deadly, and he wielded his weed whacker with a certain undeniable malevolence.”)

Left unmolested by Ewell’s corps, the Union position (as commanding Gen. George R. Meade saw when he showed up at midnight on July 1 to reconnoiter) was exceptional. As any tour guide will tell you, it resembles a fishhook, laid out on a series of hills and ridges. If, due to a series of peculiar life choices, you have never seen a fishhook, it’s basically a candy cane with a barb on one end. If you want to attack it, which the Confederates did, you had to go uphill, often facing artillery — never exactly an appealing prospect, in the sense that — well, charging uphill into cannon fire is never exactly appealing. On a list of ways to spend an afternoon it ranks far, far below going to a wine tasting with a couple whose company you find unpleasant.

The Confederates could have sought another more defensive position — or opt to attack the Union where they were. Corps commander James Longstreet, whose I Told You So role in this battle has become the stuff of legend, urged the former. Lee went with the latter. “No,” he said, as reported in “Robert E. Lee: A Biography,” “the enemy is there and I am going to attack him there.”

July 2 was a day of delay and poor coordination. Lee aimed for the flanks of the Union position, one of which had mistakenly deployed quite a bit in front of the rest of the position, creating a seriously dangerous situation for the Northern troops, but the attacks took place later than planned — in Longstreet’s case, hours later. Around 11 a.m., Lee actually found him and asked why he hadn’t attacked yet. Compared to General Longstreet, General Ewell the night prior was absolutely raring at the bit. Longstreet took his time, taking an elaborate approach march and not hitting the Union position until afternoon. The fighting was fierce, but the position held. The fishhook was battered but remained unbroken.

But there was still enough energy for another day of fighting. The missing cavalry had just arrived, and the Confederates had high hopes. After all, Pickett’s division was still fresh. Maybe they could charge, or something.