Then that is not a crime.

Read this landmark case if you can: http://en.wikipedia.org/wiki/Brandenburg_v._Ohio

Here are some excerpts：
 

In this
case, The KKK leader Brandenburg made some recording films which contains
speech like "vengeance against niggers, Jews and those who supported them”, "Personally, I believe the nigger should be
returned to Africa, the Jew returned to Israel." Some rally and
some people carrying firearms are recorded in the films. These films were later
broadcast on the local station and on a national network.  Brandenburg was
fined $1,000 and sentenced to one to ten years in prison by local government.
 

The U.S. Supreme Court reversed Brandenburg's conviction, holding that government
cannot constitutionally punish abstract advocacy of force or law violation.
 

"the constitutional guarantees of free speech
and free press do not permit a State to forbid or proscribe advocacy of the use
of force or of law violation except where such advocacy is directed to inciting
or producing imminent lawless action".^[31][32] Brandenburg is now the standard applied
by the Court to free speech issues related to advocacy of violence”