It must not be supposed that the important political measures and results thus far summarized were accomplished by quiet and harmonious legislation. Rising steadily after 1820, the controversy over slavery became deep and bitter, both in Congress and the country. Involving not merely a policy of government, but a question of abstract morals, statesmen, philanthropists, divines, the press, societies, churches, and legislative bodies joined in the discussion. Slavery was assailed and defended in behalf of the welfare of the state, and in the name of religion. In Congress especially it had now been a subject of angry contention for a whole generation. It obtruded itself into all manner of questions, and clung obstinately to numberless resolutions and bills. Time and again it had brought members into excited discussion, and to the very verge of personal conflict in the legislative halls. It had occasioned numerous threats to dissolve the Union, and in one or more instances caused members actually to retire from the House of Representatives. It had given rise to resolutions of censure, to resignations, and had been the occasion of some of the greatest legislative debates of the nation. It had virtually created and annexed the largest State in the Union. In several States it had instigated abuse, intolerance, persecutions, trials, mobs, murders, destruction of property, imprisonment of freemen, retaliatory legislation, and one well-defined and formidable attempt at revolution. It originated party factions, political schools, and constitutional doctrines, and made and marred the fame of great statesmen.