answer: The primary source document that could help a historian understand why the US Civil War started is a Charleston Mercury editorial published in 1860 because it contains factual accounts of the events during that time.
A Charleston Mercury editorial from 1860, which includes accurate details of the time's events, is a primary source text that might aid historians in understanding why the US Civil War began.
The Union and the Confederacy fought each other in the American Civil War, which took place in the United States. Slavery's legal position, particularly its spread into new areas obtained as a result of the Louisiana Purchase and the Mexican-American War, was the main driver of the conflict.
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