 Benjamin worked to deny Douglas the 1860 Democratic presidential nomination , feeling he had turned against the South . Douglas contended that although the Supreme Court , in Dred Scott v. Sandford , had stated Congress could not restrict slavery in the territories , the people of each territory could pass legislation to bar it . This position was anathema to the South . Benjamin praised Douglas 's opponent in his re @-@ election bid , former congressman Abraham Lincoln , for at least being true to his principles as an opponent of the expansion of slavery , whereas the senator considered Douglas to be a hypocrite . Benjamin was joined in his opposition to Douglas by Senator Davis ; the two were so successful that the 1860 convention was not able to nominate anyone and split into Northern and Southern factions . The Northerners backed Douglas while Southern delegates chose Vice President John C. Breckinridge of Kentucky . Despite their agreement in opposing Douglas , Benjamin and Davis differed on some race issues : in May , Benjamin voted for a bill to aid Africans liberated by U.S. naval vessels from illegal slave ships , in order to return them to their native continent from Key West . Davis and many other Southerners opposed the bill . 
