Lincoln probably would have loved drones, but may have held off using them to kill for strategic reasons
First off, Lincoln was obsessed with military technology and innovation, so there’s little question that he would have been intrigued by drones, had they been invented in the 1860s. He often personally witnessed demonstrations of new inventions and pushed for their advancement and field testing through the War Department bureaucracy, in part by promoting officers who held a similar love of innovation. Under his tenure, the Union became one of the world’s first militaries to use repeating rifles (a vast improvement over the single-shot muzzle-loaders it replaced), rifled artillery, machine guns, rockets, armored “ironclad” warships, and torpedoes, and he made advanced strategic use of railroads and especially the telegraph.
He would have loved to have had drones’ surveillance power, as he championed the unprecedented use of balloons to spy on the enemy. When the aging head of the Army initially rejected the balloon idea, Lincoln personally marched inventor Thaddeus Lowe to the War Department and declared that he would be head of the new Aeronautics Corps for the Army. “I have pleasure in sending you this first dispatch ever telegraphed from an aerial station and in acknowledging indebtedness to your encouragement for the opportunity of demonstrating the availability of the science of aeronautics in the military service of the country,” Lowe telegraphed to the president from a balloon over the National Mall.
But obviously drones did not exist in Lincoln’s day. So what about some kind of analogous technology that could safely kill enemies without a battle. Would Lincoln have been morally and legally comfortable with that?