I the Historian: Examine the Validity of the following statement: To what extent was Nationalism the true cause of World War One? (in your evaluation determine the extent nationalism was the true cause (greater moderately and lesser) and explain how significant other causes were in the outbreak of the War) - Respond to the question in your written response. 8 It can be reasonably argued that Nationalism was the (most, moderately ,least) significant cause of World War One. The most significant cause of World War one is this can be verified in the following ways. "(then go on to support your arguments with evidence from the source and your knowledge of historical circumstances)