Which agreement established the concept: For every Free State there will be a Slave State?

• A. Compromise of 1850
• B. Tariff Compromise
• C. Popular Sovereignty Plan
• D. Missouri Compromise

Answer: (D)

The concept being tested is balancing political power between free and slave states in Congress. The Missouri Compromise of 1820 established this balance by admitting Missouri as a slave state and Maine as a free state, so the Senate would remain evenly split between free and enslaved states. It also set a geographic line at 36°30′ north latitude for future territories of the Louisiana Purchase, with slavery prohibited north of that line (except for Missouri). This created a concrete mechanism to maintain equal representation between free and slave states as new states entered the Union. The other options address different issues or approaches (such as letting residents decide slavery in new territories, or focusing on tariffs), but they do not establish the enduring balance between free and slave states in the way the Missouri Compromise did.