Which primary source document could help a historian understand why the US Civil War started?

Why was "impressment" an important issue during the jefferson administration? the united states was being treated disrespectfully, as the spanish navy was forcing american sailors into naval service for them. the united states was being treated disrespectfully, as the french navy was forcing american sailors into naval service for them. the united states was treating british navy with disrespect by forcing british sailors into naval service for them. the united states was being treated with disrespect on the high seas, as the british navy was forcing american sailors off their ships and into naval service for them. the united states was treating french navy with disrespect by forcing french sailors into naval service for them.