What is the test for an "overbreadth" section of a federal anti-bullying statute?

It is a clearly established principle of constitutional law, however, that the mere fact that one can conceive of some impermissible applications of a statute is not sufficient to render it susceptible to an overbreadth challenge. On the contrary, the requirement is that the overbreadth of a statute, particularly where conduct and not merely speech is involved * * * must not only be real, but substantial as well (Broadrick v. Oklahoma, 413 U.S. 601, 615, 93 S.Ct. 2908, 2917-18, 37 L.Ed.2d 830 (1973)).