Lee at the Alamo is an alternate history short story by Harry Turtledove.
Lee concludes that it is his duty to defend U.S. Army munitions and property in San Antonio, Texas, including the fabled Alamo, rather than to allow their surrender to the seceding Texas government, as Twiggs did in real life.
Lee is forced to surrender to Benjamin McCulloch after several weeks of siege but becomes a national hero.
After Virginia eventually secedes, US President Abraham Lincoln is able to convince Lee to stay in the Union's service by agreeing to send him west, where he will not be fighting against his fellow Virginians.
"Lee at the Alamo" was nominated for a Sidewise Award for Alternate History in 2012.