"If slavery, limited as it yet is, now threatens to subvert the Constitution, how can we as wise and prudent statesmen, enlarge its boundaries and increase its influence, and thus increase already impending dangers?"

This quote by William H. Seward speaks to the dangers of slavery and its prospective to undermine the Constitution. Seward is warning that if slavery is enabled to continue in its current kind, it will ultimately lead to the damage of the Constitution. He is asking how wise and sensible statesmen can prevent this from happening by not expanding the limits of slavery and its impact. Seward is warning versus any further expansion of slavery, as it will just increase the already impending risks. He is prompting statesmen to take action to prevent the further spread of slavery and its influence, in order to protect the Constitution and the nation.