What is the test for determining whether a particular statute is or is not too broad in the constitutional sense?

In the final analysis, the determination that a particular statute is or is not too broad in the constitutional sense turns not so much on its language as upon its effect. A statute may be phrased in words that are 'broad,' in that they convey general rather than specific concepts, and yet be the means of stating a regulation that is narrow and limited in its application. (See for example the two ordinances involved in Saia v. New York, 334 U.S. 558, 68 S.Ct. 1148, 92 L.Ed. 1574, and Kovacs v. Cooper, 336 U.S. 77, 69 S.Ct. 448, 93 L.Ed. 513.) Such is respondent's rule. It is not phrased as a regulation, in that it does not enumerate specific acts which may or may not be performed on school property. It is cast in words of prohibition, in that it effectively prohibits the use of the property if the applicant intends to commit any crime on those premises. The fact that it embraces any illegal act does not make it too broad, in the constitutional sense. (See Kovacs v. Cooper, supra.)