Judge Brandeis, in his dissenting concurrence in WHITNEY V. CALIFORNIA, says "The mere act of assisting in forming a society for teaching syndicalism, of becoming a member of it, or of assembling with others for that purpose, is given the dynamic quality of crime."
The word "mere" indicates a "prior restraint" analysis: the recognition of a crime before it happens. Prior restraint is the "ounce of prevention" argument advanced by counsel in Tinker v Des Moines, but not persuasively.
Organization for a Better Austin is a case where restraint on the distribution of handbills was struck down. Prior restraint is a recognition of a harm "too soon", before "it" has occurred, and where the occurrence of the harm is uncertain or can be minimized by other means, and where remedies are possible if harm should occur.