The following reveals the Northern perception of the American South’s weakness in time of war, and this certainly was well understood by Lincoln and his advisors.
Faced with dwindling enlistments after mid-1862, Lincoln was forced to play a last card and follow the British emancipation proclamations of 1775 (Lord Dunmore of Virginia) and 1814 (Vice-Admiral Sir Alexander Cochrane) with his own. The primary intent was to incite a brutal race war, while invading Northern soldiers carried off black agricultural workers to starve the Southern armies. Those workers would also be enlisted for labor on fortifications and supply depots, and sadly employed as expendable assault troops to save white soldiers lives.
Author (below) Richard Hildreth (1807-1865) was born in Massachusetts, a Harvard graduate, and studied law at Newburyport – once an important port for ships engaged in the transatlantic slave trade. He published the following in 1854.
The South’s Weakness
“The military strength of states has ever been esteemed of the highest importance in a political point of view; since it is upon their military strength that states are often obliged to depend for their defence against internal, as well as external foes. In this particular the slave-holding States of the South present an aspect of extreme weakness.
The hardy cultivators of the soil, when driven to the dire necessity of beating their plough shares into swords, have ever furnished the best and most patriotic soldiers . . . men of this class composed those armies of the revolution to whose courage, fortitude and patient spirit of endurance, we are indebted for our national independence.
But in the slave States, these cultivators of the earth . . . would in that hour be regarded with more dread and terror even than the invaders themselves. In case of a threatened invasion, so far from aiding in the defence of the country, they would create a powerful diversion in favor of the enemy.
[It] is not likely, in case the United States became involved in war with any people of Europe, that any repugnance would be felt on the part of a hostile state, in seeking aid at the hands of the slaves. A lodgment being effected upon some part of the Southern coast, by an army of respectable strength, and emancipation being promised to all such slaves as would join the invaders, a force would soon be accumulated which the unassisted efforts of the slave-holding States would find it impossible to resist.
If the invaders were expelled it would only be by troops marched from the North. In such a crisis the fear of outbreaks on their own plantations would keep the planters at home; or if they assembled in force to resist the invaders, their absence would be likely to produce such outbreaks. When a servile was added to a foreign war, between the rage of the masters and the hatred of the slaves, it would assume a most savage aspect.
Should the slave-holding States become involved in a war, which it would be necessary for them to prosecute from their own resources, they would be obliged to depend upon a standing army levied from among the dregs of the population. Such an army would be likely to become quite as much an object of terror to those for whose defence it would be levied, as to those against whom it would be raised.”
(Despotism in America: An Inquiry into the Nature, Results and Legal of the Slave-Holding System in the United States, Richard Hildreth, John P. Jewett & Co., 1854, excerpts pp. 107-110)