The Civil War History by Ward, Page 17 3rd paragraph
"Already outvoted in the House, where the rapid growth of the Northern Population had long since overwhelmed their Representatives, the South still held parity in the Senate. Now they saw the spread of slavery into that great western emptiness as essential to their survival: unless the new states to be carved from it were to prevent slavery, the South would find itself at the mercy of Northern senators interested only in exploiting it."
"What do you propose, gentlemen of the Free soil party?" (then) Senator Jefferson Davis of Mississippi once challenge his northern colleagues "Do you propose to better the condition of the Slave? Not at all...You say you are opposed to slavery...is the slave benefited by it? Not at all. It is not humanity that influences you...it is that you may have an opportunity of cheating us that you want to limit slave territory... it is that you may have a majority in the Congress of the United States and convert the Government into an engine of Northern Aggrandizement...you want an unjust system of legislation to promote the industry of the United States at the expense of the people of the South."
"Only the most militant Garrisonians had ever argued that congress was empowered to bar slavery from the states. But for many Northerners, these vast new western territories were another matter; for them, it was unthinkable that the American Flag should imposes the South's "peculiar institution" on new lands hard won by Americans from Every part of the Country."