The first of these changes was the inevitable attack upon slavery. The labor system of the seceding States was a mark so tempting that no belligerent should have been seriously expected to have refrained from aiming at it. January 1, 1863, after one hundred days' notice, President Lincoln issued his Emancipation Proclamation, freeing the slaves within the enemy's lines as rapidly as the Federal arms should advance. This one break in the original policy involved, as possible consequences, all the ultimate steps of reconstruction. Read-mission was no longer to be a simple restoration; abolition of slavery was to be a condition-precedent which the government could never abandon. If the President could impose such a condition, who was to put bounds to the power of Congress to impose limitations on its part? The President had practically declared, contrary to the original policy, that the war should continue until slavery was abolished; what was to hinder Congress from declaring that the war should continue until, in its judgment, the last remnants of the Confederate States were satisfactorily blotted out? This, in effect, was the basis of reconstruction, as finally carried out. The steady opposition of the Democrats only made the final terms the harder. The principle urged consistently from the beginning of the war by Thaddeus Stevens, of Pennsylvania, was that serious resistance to the Constitution implied the suspension of the Constitution in the area of resistance. No one, he insisted, could truthfully assert that the Constitution of the United States was then in force in South Carolina; why should Congress be bound by the Constitution in matters connected with South Carolina? If the resistance should be successful, the suspension of the Constitution would evidently be perpetual; Congress alone could decide when the resistance had so far ceased that the operations of the Constitution could be resumed. The terms of readmission were thus to be laid down by Congress. To much the same effect was the different theory of Charles Sumner, of Massachusetts. While he held that the seceding States could not remove themselves from the national jurisdiction, except by successful war, he maintained that no Territory was obliged to become a State, and that no State was obliged to remain a State; that the seceding States had repudiated their State-hood, had committed suicide as States, and had become Territories; and that the powers of Congress to impose conditions on their readmission were as absolute as in the case of other Territories. Neither of these theories was finally followed out in reconstruction, but both had a strong influence on the final process.