Final answer:
Senator Norris opposed U.S. entry into World War I due to a blend of isolationism, the belief that the conflict did not pertain to the U.S., anti-imperialist sentiments, concerns over Wall Street profiteering, and worries about over-commitment through the League of Nations.
Step-by-step explanation:
Senator Norris represented a segment of American policymakers who opposed U.S. entry into World War I for several reasons. Key among these reasons were a desire to maintain U.S. neutrality in European conflicts as many Americans saw the war as one that did not concern the United States. This perspective was influenced by various factors, including the ethnic composition of the U.S. population, with many citizens having roots in the countries involved in the conflict. The opposition also stemmed from anti-imperialist sentiments, with some believing that the war would only serve to enrich Wall Street bankers and munitions makers at the expense of ordinary citizens. Additionally, the fear that involvement in the League of Nations could entangle the U.S. in international disputes without the Senate's consent was paramount. These concerns aligned with the prevailing isolationist sentiment, intensified by the findings of the Nye Committee that investigated the role of the so-called 'merchants of death' in U.S. entry into WWI.