But the wickedness which I now begin to expose is immeasurably aggravated by the motive which prompted it. Not in any common lust for power did this uncommon tragedy have its origin. It is the invasion of a virgin Territory, compelling it to the hateful embrace of Slavery; and it may be clearly traced to a depraved longing for a new slave State, the hideous offspring of such a crime, in the hope of adding to the power of slavery in the National Government. Yes, sir, when the whole world, alike Christian and Turk, is rising up to condemn this wrong, and to make it a hissing to the nations, here in our Republic, force -- aye, Sir, FORCE, -- has been openly employed in compelling Kansas to this pollution, and all for the sake of political power. There is the simple fact, which you will vainly attempt to deny, but which in itself presents an essential wickedness that makes other public crimes seem like public virtues.” - Senator Charles Sumner, 1856

The excerpt most directly reflects which of these conflicts?
A) the debate over immigration and the rise of “Nativism”
B) the debate over slavery and its extension into the western territories
C) the military seizure and occupation of Native American lands in the western territories
D) the war with Mexico and disagreement in the Senate over the Treaty of Guadalupe-Hidalgo