The cautious policy foreshadowed in his inaugural address, and pursued during the first period of the civil war, was far from satisfying all his party friends. The ardent spirits among the Union men thought that the whole North should at once be called to arms, to crush the rebellion by one powerful blow. The ardent spirits among the antislavery men insisted that, slavery having brought forth the rebellion, this powerful blow should at once be aimed at slavery. Both complained that the administration was spiritless, undecided, and lamentably slow in its proceedings. Lincoln reasoned otherwise. The ways of thinking and feeling of the masses, of the plain people, were constantly present to his mind. The masses, the plain people, had to furnish the men for the fighting, if fighting was to be done. He believed that the plain people would be ready to fight when it clearly appeared necessary, and that they would feel that necessity when they felt themselves attacked. He therefore waited until the enemies of the Union struck the first blow. As soon as, on the 12th of April, 1861, the first gun was fired in Charleston harbor on the Union flag upon Fort Sumter, the call was sounded, and the Northern people rushed to arms.
Lincoln knew that the plain people were now indeed ready to fight in defence of the Union, but not yet ready to fight for the destruction of slavery. He declared openly that he had a right to summon the people to fight for the Union, but not to summon them to fight for the abolition of slavery as a primary object; and this declaration gave him numberless soldiers for the Union who at that period would have hesitated to do battle against the institution of slavery. For a time he succeeded in rendering harmless the cry of the partisan opposition that the Republican administration were perverting the war for the Union into an “abolition war.” But when he went so far as to countermand the acts of some generals in the field, looking to the emancipation of the slaves in the districts covered by their commands, loud complaints arose from earnest antislavery men, who accused the President of turning his back upon the antislavery cause. Many of these antislavery men will now, after a calm retrospect, be willing to admit that it would have been a hazardous policy to endanger, by precipitating a demonstrative fight against slavery, the success of the struggle for the Union.