NAEP Civics Grade 12

"We admit that in . . . ordinary times the defendants . . . would have been within their constitutional rights. But the character of every act depends upon the circumstances in which it is done. The most stringent protection of free speech would not protect a man in falsely shouting fire in a theater and causing a panic. . . . The question in every case is whether the words used 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 evils that Congress has a right to prevent."

What argument is the Supreme Court making in this decision?