To what extent was westward expansion the main cause of the Civil War?

The question requires that candidates consider the merits or otherwise of the suggestion that westward expansion was the main cause of the Civil War. Causes may predate the timeframe but they must be clearly linked to the issue raised in the question. Candidates may offer equal coverage of evidence supporting the suggestion and evidence opposed to the suggestion or they may prioritize their assessment of either position. However, both aspects will be a feature of the response. Candidates may refer to the Southern demands for westward expansion caused by “soil exhaustion”, the expansionist impact of the Mexican War and the effects of popular sovereignty as illustrated by the Kansas-Nebraska Act. Other relevant factors may be addressed, for example the failures of leadership as exhibited by James Buchanan, the growth of irreconcilable economic differences between the North and South and the impact of crisis events (for example, John Brown’s raid or the Dred Scott Supreme Court decision), but with a focus on the issue in the question. Candidates’ opinions or conclusions will be presented clearly and supported by appropriate evidence.

The question as to what extent did westward expansion cause the Civil War was a very popular choice and produced a wide range of responses as to quality. Most candidates acknowledged that westward expansion was at least a significant cause of the Civil War though the majority cited slavery as the main cause. Knowledge of the political compromises which emanated from the addition of southern and western states was extensive but often presented in a narrative with limited analysis as to how it contributed to the start of the war.