Answer:
Effective because President Wilson outlines the emotional reasons for entering the war.
Step-by-step explanation:
I don't know what the speech is, but based on the WWI era, this makes the most sense. Americans chose Wilson as president with the popular phrase in mind: "he kept us out of war!" So, for Wilson to encourage people that war is the best way to go, he would need to appeal to their emotions.
Again, this could be wrong because the source wasn't given.