One reason the Missouri Compromise did not have lasting effects is that it only temporarily resolved the issue of slavery in the territories, rather than addressing it as a long-term solution. The compromise allowed Missouri to enter the Union as a slave state and Maine as a free state, and it drew a line across the Louisiana Purchase territory, with slavery being allowed south of the 36°30' parallel and prohibited north of it. However, this line was eventually deemed unconstitutional by the Supreme Court's decision in the Dred Scott case in 1857. This ruling led to the further division and polarization of the nation over the issue of slavery, ultimately culminating in the American Civil War. Therefore, the Missouri Compromise's limited scope and temporary nature prevented it from truly resolving the underlying tensions surrounding slavery, resulting in its lack of lasting effects.
