Actually the sinking of the Americans ships was justified for Germany as they were trying to hind down supply ships for britain and the lusatannia was one that carried weapons to Britain. The United States of America knew that so they planned a war against Britiain but it didn't matter as then Germany sent the Zimmerman and payed for it by getting on uncle Sam's bad side.
Answer:
Legislative: makes all laws, declares war, regulates interstate and foreign commerce and controls taxing and spending policies.
Executive: responsible for enforcing the laws of the land
Judicial: According to the Constitution, "[t]he judicial Power of the United States, shall be vested in one supreme Court, and in such inferior Courts as the Congress may from time to time ordain and establish." The Federal Judicial Center is the education and research agency for the federal courts. They also interprets the laws. The state judges are elected by the citizens rather than being appointed.
(sorry about only 1 job for the Executive branch)
