According to the bolded lines, what is one reason for schenck's indictment? he organize a mail campaign for the military. he tried to send something through the mail illegally. he tried to encourage men to sign up for enlistment. he tried to join the united states navy.

According to the indictment against him, Charles Schenck tried to send something through the mail illegally.

Charles Schenck was a Socialist Party leader in the US who opposed US participation in World War I.  He mailed pamphlets to men who'd been drafted that said the government had no right to send American citizens to war to kill people in other countries.  Schenck was convicted of violating the Espionage Act, which had been passed by Congress in 1917.

Schenck appealed his case to the Supreme Court, saying the Espionage Act was unconstitutional.   In the 1919 decision in Schenck v. United States, the Supreme Court upheld the conviction against Schenck.  Thus the Court essentially upheld the constitutionality of the Espionage Act at that time, saying that in wartime the government has extra responsibility to protect the safety of the nation.  The decision, written by Justice Oliver Wendell Holmes, said, "The question in every case is whether the words are used in such circumstances and are of such a nature as to create a clear and present danger that they will bring about the substantive evils that Congress has a right to prevent."