Today is the 145th anniversary of the first day of the battle of Gettysburg. It was this day that, in my opinion, truly decided the course of the battle and the tide of the war. With the the entire Confederate army moving towards Gettysburg from Chambersburg and Carlisle, Union cavalry commander General John Buford orchestrated what's called a "defense in depth" in order to prevent Lee's army from seizing the all-important high ground positions around the town -- Confederates had exploited similar positions for bloody victories at Fredericksburg and Second Manassas.
So the defense in depth... Buford created defensive positions west and north of town knowing that his small division of dismounted and outnumbered horsemen would not be able to hold against two or more Confederate corps (a single corp is composed of at least three divisions -- much larger than Buford's forces). But the lines would hold long enough for more federal infantry to come up from Emmitsburg. And by the time reinforcements would arrive, the Union lines would have been pushed back to the very desirable high ground south and west of Gettysburg -- but with the entire Union army finally having arrived to defend the new positions.
And that's what happened. The Confederates overwhelmed Buford's troops along with the Union First Corp and they fell back at nightfall to the advantageous high ground. Meanwhile, the Second Corp and 12th Corp had arrived on the field to fortify the hills, with more federal troops flooding into position every hour and into Day Two (a day in which my great-great grandfather helped to defend Little Round Top).
These Union high ground positions on Culp's Hill, Cemetary Hilll and the high ridges to the south would be nearly impossible to break for the rest of the battle. For the first time in the eastern theater of the war, the Union had attained a key battlefield advantage against General Lee -- and this advantage was the factor that, to me, ultimately decided the battle. So it can be said that General John Buford from Kentucky, a soldier whose name is often forgotten, saved the Union and helped to free an entire race of Americans that day.
Sam Elliot as General Buford in the movie Gettysburg waits for the First Corp to arrive.