Do you have options? If not I can list a few:
Illegal drugs.
Illegal Weapons.
Illegal stuff.
Unregistered people.
Terrorists.
This is a conflict of individual rights versus state protection. For some, the individual rights come first even if it is an attack on others or could put the country at risk. For others, the protection of the country is more important and therefore a person who speaks in a way that threatens the country should and can be silenced.
Schenck v. US is a famous case where the court ruled if the speech presents a danger to the country then the 1st Amendment right is not applicable and can be denied.
Tinker v. Des Moines School District demonstrated when a person peacefully protest even in a school against the government and their decisions (Vietnam War in this case), then the 1st Amendment is applied and the individual rights upheld.
