SerenityHeart SerenityHeart 17-12-2020 History contestada What is the best description of the long-term goal of the Mason-Dixon Line and the Missouri Compromise? Prevent “Free” states from overpowering “Slave” states in Congress. Bring the US to the brink of war to settle the issue of slavery once and for all. Prevent “Slave” states from overpowering “Free” states in Congress. Keep the balance between “Free” and “Slave” states to keep the peace.