Lincoln’s followers emulated Virginia’s Royal Governor Dunmore’s rationale for emancipating slaves in 1775, that is, to fight against an independence movement by colonists and deprive them of agricultural labor. Northern radical Republicans such as Henry Wilson of Massachusetts, wanted to liberate slaves in Southern States where they could not reach them, but did not free the property of slave holders loyal to Lincoln.
Bernhard Thuersam, www.Circa1865.com
Weakening the Forces of the Rebellion
“When the Rebellion culminated in active hostilities, it was seen that thousands of slaves were used for military purposes by the rebel forces. To weaken the forces of the Rebellion, the Thirty-seventh Congress decreed that such slaves should be free forever.
As the Union armies advanced into the rebel States, slaves, inspired by the hope of personal freedom, flocked to their encampments, claiming protection against rebel masters, and offering to work and fight for the flag whose stars for the first time gleamed upon their vision with the radiance of liberty.
To weaken the power of the insurgents, to strengthen the loyal forces, and assert the claims of humanity, the Thirty-seventh Congress enacted an article of war, dismissing from the service officers guilty of surrendering these fugitives [to rebel masters].
The hoe and spade of the rebel slave were hardly less potent for the Rebellion than the rifle and bayonet of the rebel soldier. Slaves sowed and reaped for the rebels, enabling the rebel leaders to fill the wasting ranks of their armies, and feed them.
To weaken the military forces and power of the Rebellion, the Thirty-seventh Congress decreed that all slaves of persons giving aid and comfort to the Rebellion, escaping from such persons, or deserted by them; all slaves of such persons, being within any place occupied by the forces of the United States, — shall be captives of war, and shall be forever free of their servitude, and not again held as slaves.
The progress of the Rebellion demonstrated its power, and the needs of the imperiled nation. To strengthen the physical forces of the United States, the Thirty-seventh Congress authorized the president to receive into military service persons of African descent; and every such person mustered into the service, his mother, his wife and children, owing service or labor to any person who should give aid and comfort to the Rebellion, was made forever free.
The African slave trade had been carried on by slave pirates under the protection of the flag of the United States. To extirpate from the seas that inhuman traffic, and to vindicate the sullied honor of the nation . . . the administration entered early into treaty stipulations with the British Government . . .”
(Life and Public Services of Henry Wilson, Rev. Elias Nason and Thomas Russell, B.B. Russell, 1876, pp. 346-349)