Final answer:
A key detail in "Wilson's War Message to Congress" that supports his argument for entering the war is Germany's sinking of sea vessels regardless of nationality.
Step-by-step explanation:
In "Wilson's War Message to Congress", a key detail that supports his argument for entering the war is that Germany has sunk sea vessels regardless of the vessel's nationality. This demonstrates the aggressive and indiscriminate actions of Germany, which Wilson argues pose a threat to international peace and safety. By highlighting this fact, Wilson seeks to justify the need for the United States to join the war in order to protect its own interests and uphold democratic values.
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