What was the one of the first military measure used by the US during WW1? How successful was it?

When the World War 1 took place, American President Woodrow Wilson said that America would stay neutral on the war and continued to send goods to the war countries. However a German submarine sank in the British ocean liner near Lusitania which made death casualty of nearly 1200 people in which 128 were Americans.

After this incident, President Wilson became fierce and threatened Germany to stop unannounced submarine warfare, he was reluctant for the US to go to a war with Germany. The one of the first measures the US took during WW1 was to sign the National defence act to expand the Army and the National guard, a legislation was also signed to strengthen the Navy.