Final answer:
The direct effect of the Missouri Compromise was to appease both the North and South by maintaining a balance between free and slave states in the Union, but it did not address the root issues of slavery, leading to increased hostility between the regions.
Step-by-step explanation:
The Missouri Compromise, established in 1820, was a legislation that worked to maintain the balance between free and slave states in the United States. The primary direct effect of the Missouri Compromise was that it sought to appease both the North and the South by allowing Missouri to enter the Union as a slave state while Maine entered as a free state, preserving the balance of power in Congress. This compromise temporarily eased tensions between the two regions, but it did not address the underlying issues surrounding slavery, ultimately contributing to increased hostility between the North and South.