According to David Herbert Donald in his article, “Why the War Came: The Sectional Struggle over Slavery in the Territories,” “containment” according to the North meant that in order to ensure slavery did not overtake free states, it must be held only to the locality where it currently operated. The North believe wholly in the “expand or die” philosophy regarding slavery, in conclusion, if slavery were allowed to creep into the new territories of America, it would also reach it's influence to the free states(Donald). For example the Northern free-soilers presumed, “If the extension of slavery could be prevented, they concluded the whole system must collapse”(Donald). Therefore if slavery could be held to the established areas in the South,
