The Senate campaign featured seven debates between the two. These were the most famous political debates in American history; they had an atmosphere akin to a prizefight and drew crowds in the thousands. The principals stood in stark contrast both physically and politically. Lincoln warned that Douglas’ 'Slave Power' was threatening the values of republicanism, and accused Douglas of distorting the Founding Fathers' premise that all men are created equal. Douglas emphasized his Freeport Doctrine, that local settlers were free to choose whether to allow slavery, and accused Lincoln of having joined the abolitionists. Lincoln's argument assumed a moral tone, as he claimed Douglas represented a conspiracy to promote slavery. Douglas's argument was more legal, claiming that Lincoln was defying the authority of the U.S. Supreme Court in the Dred Scott decision.