riddle - separate with a riddle, as grain from chaff screen sift, sieve, strain - separate by passing through a sieve or other straining device to separate out coarser elements; sift the flour
Causes of the Civil War: Slavery and Control of the Government. Throughout the first half of the 19th century, Southern politicians sought to defend slavery by retaining control of the federal government.
Causes of secession. The causes of the Civil War were complex and have been controversial since the war began. James C. Bradford wrote that the issue has been further complicated by historical revisionists, who have tried to offer a variety of reasons for the war. Slavery was the central source of escalating political tension in the 1850s.