Final answer:
The Espionage Act protected the Postmaster General's right to ban and confiscate mail encouraging people to disobey the military draft.
Step-by-step explanation:
The Postmaster General's right to ban and confiscate any mail that encouraged people to disobey the military draft was protected by the Espionage Act. This act was passed in 1917 by the U.S. Congress during World War I to address the issue of individuals interfering with the war effort. It made it a crime to convey false information, interfere with the military, or promote insubordination or disloyalty.
Learn more about Espionage Act and mail censorship