They may prefer appointment of judges rather than election to avoid having judges who have biases towards cases & people that they judge upon? (Hopefully that helps a little, I hope it isn't confusing)
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Answer: Slavery was a point of contention in the United States since the country's founding. The disagreement intensified as the 1800s began. In 1820, the Missouri Compromise established a boundary that wouldn't allow new slave states above this line. Dred Scott had been taken by his owner to an area in which slavery had been made illegal because of the Missouri Compromise.
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