Here surely was cause enough for controversy. And a new reason had arisen for intense obstinacy in controversy. Let us consider this a little carefully. The anti-slavery agitation at the North was growing more and more aggressively hostile. In common with the pro-slavery sentiment at the South it had begun to appeal to the old and dying sentiment of states' rights for the justification of its attitude, thus reviving a controversy between the national sovereignty and the independence of the states, which had been largely allayed by the progress of time. Northern states refused to make themselves parties to slavery even at command of the Federal Government. They refused to lend their courts and jails and sheriffs to the work of returning to slavery negroes who had run away from bondage at the South. They enacted laws in assertion of their State sovereignty which in effect nullified the laws of the Nation and effectually obstructed their execution. We are writing now of the period from 1845 to 1860, and not of a particular year. Here was that revival of the old states' rights controversy with the Federal authority, of which mention has been made before. It was met on the other side by an equally determined assertion of states' rights. There was nowhere any question that every state in the Union--except as forbidden by the cession of the Northwest Territory or by the Missouri Compromise--had full authority to sanction or forbid the institution of slavery within its own borders at its own free will. But there was a party at the North which contended that slavery was a wrong so enormous that it ought to be exterminated by the high hand of Federal force; that the disruption of the Union as an incident to such extermination of the system would be a small price to pay for an end so beneficent. The abolitionists denounced the Constitution itself as "a covenant with hell," because it permitted the several states to decide for themselves whether or not they would permit African slavery within their borders, and because it authorized laws compelling the rendition of fugitive slaves. On the other hand there was growing up at the South a party that preferred the disruption of the Union to a longer continuance of existing conditions, a party weary of struggling for what it held to be the rights of the states under the Constitution and disposed instead to resort to the ultimate right of withdrawal from the Union which the South claimed then, as New England had claimed it during the war of 1812, as a reserved privilege of the states. The slavery question had not only entered again into national politics, but had become well-nigh the only question of politics, state and national.