Northern industrialists needed a justifiable system that could still be seen as congruent with American ideals but could still allow cheap or next to free labor. Slavery was an embarrassment and the trade of goods being manufactured in the North would run into problems if it was being done within a slave system of which the rest of the world correctly had already banned and saw as the savage system that it was. Capitalist liberalism is self serving - "tolerance" of immigrants and newly freed slaves as migrants, for example, provided a source of cheap exploitable labor. There were two sacrifices needed to save capitalism - Republican abolition and later the Keynesian Democratic New Deal. Both worked to the political benefit of each of the two parties in the end by maintaining economic capitalism with the veneer of political democracy...