citizens’ First Amendment rights is unexceptionable when stated in the abstract, it is unclear what exactly a litigant must establish to facially invalidate an exercise of Congress’s spending power on this ground.  In general, it is well-established that a court may sustain a facial challenge to a statute only if the plaintiff demonstrates that the statute admits of no constitutional application.  See United States v.  Salerno, 481 U.S. 739, 745 (1987) ("A facial challenge to a legislative Act is, of course, the most difficult challenge to mount successfully, since the challenger must establish that no set of circumstances exists under which the Act would be valid."); see also Bowen v.  Kendrick, 487 U.S. 589, 612 (1988) ("It has not been the Court’s practice, in considering facial challenges to statutes of this kind, to strike them down in anticipation that particular applications may result in unconstitutional use of funds.”) (internal quotation marks and citation omitted).

First Amendment overbreadth doctrine creates a limited exception to this rule by permitting facial invalidation of a statute that burdens a substantial amount of protected speech, even if the statute may be constitutionally applied in particular circumstances.  “The Constitution gives significant protection from overbroad laws that chill speech within the First Amendment’s vast and privileged sphere.  Under this principle, [a law] is unconstitutional on its face if it prohibits a substantial amount of protected expression.”  Ashcroft v.  Free Speech Coalition, 122 S. Ct. 1389, 1399 (2002); see also Broadrick v.  Oklahoma, 413 U.S. 601, 612 (1973).  This more liberal test of a statute’s facial validity under the First Amendment stems from the recognition that where a statute’s reach contemplates a number of both constitutional and unconstitutional applications, the law’s sanctions may deter individuals from challenging the law’s validity by engaging in constitutionally protected speech that may nonetheless be proscribed by the law.  Without an overbreadth doctrine, “the contours of regulation would have to be hammered out case by case – and tested only by those hardy enough to risk criminal prosecution to determine the proper scope of regulation.”  Dombrowski v.  Pfister, 380 U.S. 479, 487 (1965); see also Brockett v.  Spokane Arcades, Inc., 472 U.S. 491, 503 (1985) ("[A]n individual whose own speech or expressive conduct may validly be prohibited or sanctioned is permitted to challenge a statute on its face because it also threatens others not before the court – those who desire to engage in legally protected expression but who may refrain from doing so rather than risk prosecution or undertake to have the law declared partially invalid.").