Because the Constitution could sanction emancipation only as one of the war powers, freeing slaves could only be justified as a means of winning the war and suppressing the Southern rebellion. As a result, until the very end of the war Lincoln claimed that the purpose of the war was the restoration of the Union. Southern leaders denounced Lincoln as a bloodthirsty revolutionary whose emancipation policies proved that the secessionists were right all along about those they labeled "Black Republicans." Northern Democrats, meanwhile, denied that emancipation was a "military necessity," as Lincoln and the Republicans claimed it was. But Lincoln never deviated from his official position, that because the Constitution recognized slavery in the states the only constitutional justification for freeing slaves was the restoration of the Union.