Fort Pickens in Florida was a backwater of the Civil War. Built in the 1830s on a barrier island to protect the entrance to Pensacola Bay, Union forces manned it at the start of the Civil War, and unlike Fort Sumter, Pickens would stay in Union hands for the entire war despite at least one determined Confederate assault that tried to take it in October 1861.
Like other Union military posts Fort Pickens became a magnet for slaves desperate to be free. As described in the March 10 edition of Civil War Emancipation, when confronted with the arrival of fugitive slaves seeking sanctuary on March 12, 1861, the then commander of the post, Lt. Adam J. Slemmer, promptly turned them over to the authorities in Pensacola. He reported to his superiors:
Slemmer’s action of refusing sanctuary to the slaves was consistent with the Fugitive Slave Act–under the law escaped slaves had to returned to their owners and Slemmer followed the law. Major Robert Anderson, when confronted with a runaway slave around the same time at Fort Sumter, did exactly the same thing. He sent the slave to the authorities in Charleston to be returned to his owner.
By late June 1861, Slemmer had left Fort Pickens for another assignment, and the fort was under the command of Col. Harvey Brown. A grizzled veteran of the regular army who had served since his graduation from West Point in 1818, Brown certainly was no weak sentimentalist. Yet when confronted with the arrival of escaped slaves his reaction was quite different from his predecessor. On June 21, 1861, he reported, “I shall not send the negroes back as I will never be voluntarily instrumental in returning a poor wretch to slavery but will hold them subject to orders.”
Certainly, Brown’s action was consistent with the new contraband of war policy. The slaves making their way to Fort Pickens were almost without doubt the property of disloyal slaveholders, and so subject to seizure. It also made military sense for Harvey Brown to offer sanctuary to slaves that had made the difficult journey to the fort since they were his best source of intelligence about the Confederate forces organizing themselves against him in Pensacola. Far from the North and reinforcement and resupply, local slaves were Brown’s only allies. Yet his description of a slave as a “poor wretch” also is highly significant. It reveals a grudging sympathy for them as human beings. For a four decade veteran of the Mexican War and many campaigns against Native Americans to empathize with slaves in June 1861 is quite remarkable. Clearly, in the three months from March to June 1861 something had changed.
Source: http://www.simmonsgames.com/research/authors/USWarDept/ORA/OR-S2-V1-C4.html#e13
Civil War Emancipation 