One of the main points of dispute between the Republican and Democratic parties after the Civil War was A. the degree of punishment for the South. B. policy toward Great Britain. C. high tariffs versus anti-protectionism. D. states' rights versus nationalism.

The correct answer is A. After the Civil War, one major point of dispute between the Republican and Democratic parties was the degree of punishment for the South. Republicans, particularly the Radical Republicans, argued for a strict Reconstruction policy that punished the former Confederate states and ensured civil rights for freed slaves. In contrast, Democrats typically favored more lenient treatment of the South, aiming for a quicker reconciliation without significant changes to the pre-war social order. Option B (policy toward Great Britain) and Option C (high tariffs versus anti-protectionism) were issues of the time, but they were not the primary points of contention between the two parties during the initial Reconstruction period. Option D (states' rights versus nationalism) was a central debate during the Civil War period as well, but the question specifically refers to a dispute after the war, making Option A the best choice.