In the case of Frohwerk v. United States (249 U.S. 204 (1919)), Frohwerk was publishing a
pro-German newspaper denouncing US involvement in World War I. He was
convicted of violating the Espionage Act of 1917, which basically made it a crime to make statements
that would interfere with 'military success' or obstruct 'recruiting and
enlistment' into the military, when the US was at war.
The US Supreme Court upheld
the sentence, and said that the Espionage Act was not a violation of the 1st
Amendment's right to free speech
because "the 1st Amendment was not intended to give immunity for every possible use of
This case (along with Schenck
v. United States (249 U.S. 47 (1919))
and Debs v. United States
(249 U.S. 211 (1919))) defined the clear and present danger
exception to freedom of speech,
which says that a law is constitutional if it can be shown that the
language it prohibits poses a "clear and present danger."