It was soon afterwards (August 19, 1862), that Horace Greeley published his open letter entitled "The Prayer of Twenty Millions" to which Mr. Lincoln replied, setting forth his policy and purpose, in words already quoted in this chapter: "My paramount object is to save the Union, and not either to save or destroy slavery. If I could save the Union without freeing any slave, I would do it. If I could save it by freeing all the slaves, I would do it. And if I could do it by freeing some and leaving others alone, I would also do that." But all this while Mr. Lincoln contemplated the emancipation of the slaves by executive proclamation as a war measure to be resorted to whenever it should seem to him likely to be effective. In the preceding month of July he had drawn up a proclamation of emancipation, and had read it to his cabinet. But he had laid it aside, believing that the time was not yet ripe. The Confederates seemed at that time at high tide of military success. Their armies, victorious and aggressive, were overthrowing one Federal force after another, and putting Washington itself upon an uncertain defense. It was the conviction both of Mr. Lincoln and of Mr. Seward, that to issue an emancipation proclamation under such circumstances would not only seem ridiculous in the eyes of the world but would be everywhere interpreted as a despairing manifestation of conscious weakness, the futile outcry of failure. He must wait for victories before taking this step. But when after Antietam, Lee withdrew from Maryland and abandoned his campaign against the national capital, Mr. Lincoln decided to assume the rôle of a victor, dictating terms which he held himself strong enough to enforce. Accordingly on September 22, 1862, he issued a proclamation declaring that on the first of January, 1863, all slaves held in those states or parts of states which should at that time be still in rebellion should be then and forever afterwards free. This was at once a threat and a promise. It is a matter of curious speculation to consider what would have been the situation if the Southern States had submitted themselves before the beginning of 1863. In that event the proclamation of freedom to slaves within their borders would have been of no effect, inasmuch as it applied only to states remaining at war. A second executive proclamation of emancipation would have had no war necessity to justify or even to excuse it. For the Constitution conferred upon the President no power to emancipate slaves. It was only on the plea of war necessity that this power could be remotely and speculatively inferred, and that war necessity would have passed completely away had the war itself come to an end before the date set for the enforcement of the threat. Perhaps it was in view of this very remote contingency that Mr. Lincoln at that time urged upon Congress the adoption of a constitutional amendment forbidding slavery anywhere within the borders of the Union.