Had Frank Baker, James Townsend, and Shepard Mallory escaped a few days earlier, they would certainly have been returned to their Confederate master, Colonel Charles K. Mallory. The Fugitive Slave Act of 1850, the rule of the nation, would have required it. But Virginia had just seceded, declaring itself no longer a part of the United States.
When Colonel Mallory sent a messenger to Fortress Monroe to demand return of his "property," Major General Butler was faced with a challenging decision. If he gave the three runaways back to their master, what would be their fate? Certainly, a harsh beating, if not worse. And, more important to Butler, if they survived punishment, they'd surely be put back to work building the gun battery aimed directly at Fortress Monroe. What should he do?
The shrewd lawyer-turned-general knew that in wartime a commander could seize any enemy property being used for hostile purposes—like building an artillery emplacement. And since Virginia, by its secession, was no longer a part of the United States, Butler reasoned, Virginia's citizens were no longer protected by US laws, including the Fugitive Slave Act. Therefore, Butler decreed the runaways enemy property, or "contraband of war."
It was a decision with historic consequences.
Image: From Butler's Book: Autobiography and Personal Reminiscences of Major-General Benj. F. Butler by Benjamin F. Butler, 1892.