"These attacks on slavery provoked the defense of slavery that formed the cornerstone of the Democratic Party. The Democratic Party in the South invented the "positive good" school that argued slavery was good not only for the master but also for the slave. The champion of this school was the Democratic Senator John C. Calhoun. Northern Democrats, led by Senator Stephen Douglas, produced a subtler but no less invidious apologia for slavery: "popular sovereignty," a doctrine that allowed each state and territory to decide for itself whether it wanted slavery."