This purpose has been somewhat summarily treated by American historians, largely because of lack of specific evidence as to motives at the time of issue. Two words "military necessity" are made to cover nearly the entire argument for emancipation in September, 1862, but in just what manner the military prowess of the North was to be increased was not at first indicated. In 1864, Lincoln declared that after the failure of successive efforts to persuade the border states to accept compensated emancipation he had believed there had arrived the "indispensable necessity for military emancipation and arming the blacks[874]." Repeatedly in later defence of the proclamation he urged the benefits that had come from his act and asserted that commanders in the field "believe the emancipation policy and the use of coloured troops constitute the heaviest blow yet dealt to the rebellion[875]." He added: "negroes, like other people, act upon motives. Why should they do anything for us, if we will do nothing for them? If they stake their lives for us, they must be prompted by the strongest motive, even the promise of freedom."

There is no note here of stirring a servile insurrection; nor did Lincoln ever acknowledge that such a purpose had been in his mind, though the thought of such possible result must have been present - was, indeed, present to most minds even without a proclamation of emancipation. Lincoln's alleged purpose was simply to draw away slaves, wherever possible, from their rebellious masters, thus reducing the economic powers of resistance of the South, and then to make these ex-slaves directly useful in winning the war. But after the war, even here and there during it, a theory was advanced that an impelling motive with the President had been the hope of influencing favourably foreign governments and peoples by stamping the Northern cause with a high moral purpose. In popular opinion, Lincoln came to be regarded as a far-visioned statesman in anticipating that which ultimately came to pass. This has important bearing on the relations of the United States and Great Britain.

There is no doubt that nearly every Northern American had believed in 1860, that anti-slavery England would sympathize strongly with the North. The event did not prove this to be the case, nor could the North justly complain in the face of administration denials of an anti-slavery purpose. The English Government therefore was widely upheld by British opinion in regarding the struggle from the point of view of British interests. Yet any Northern step antagonistic to the institution of slavery compelled British governmental consideration. As early as December, 1860, before the war began, Bunch, at Charleston, had reported a conversation with Rhett, in which the latter frankly declared that the South would expect to revive the African Slave Trade[876]. This was limited in the constitution later adopted by the Confederacy which in substance left the matter to the individual states - a condition that Southern agents in England found it hard to explain[877]. As already noted, the ardent friends of the North continued to insist, even after Lincoln's denial, that slavery was the real cause of the American rupture[878]. By September, 1861, John Bright was writing to his friend Sumner that, all indications to the contrary, England would warmly support the North if only it could be shown that emancipation was an object[879]. Again and again he urged, it is interesting to note, just those ideals of gradual and compensated emancipation which were so strongly held by Lincoln. In this same month the Spectator thought it was "idle to strive to ignore the very centre and spring of all disunion," and advised a "prudent audacity in striking at the cause rather than at the effect[880]." Three weeks later the Spectator, reviewing general British press comments, summed them up as follows:

     "If you make it a war of emancipation we shall think you 
     madmen, and tell you so, though the ignorant instincts of 
     Englishmen will support you. And if you follow our counsel in 
     holding a tight rein on the Abolitionists, we shall applaud 
     your worldly wisdom so far; but shall deem it our duty to set 
     forth continually that you have forfeited all claim to the 
     popular sympathy of England."

This, said the Spectator, had been stated in the most objectionable style by the Times in particular, which, editorially, had alleged that "the North has now lost the chance of establishing a high moral superiority by a declaration against slavery." To all this the Spectator declared that the North must adopt the bold course and make clear that restoration of the Union was not intended with the old canker at its roots[881].