How did the debate over the expansion of slavery lead southern politicians to insist that their safety required northern silence on slavery?

from my own personal expirence food stamps has alot this makes it eaiser so we can affod bills and so we can life a better lifestyle not needing to worry about paying actual money to buy food since most people spend 100-300 dollars a month on food so this alot so we can afford other bills and other stuff we need

not really sure i needed the points. sorry