The “void-for-vagueness” doctrine holds that a law is facially invalid if men of common intelligence must necessarily guess at its meaning and differ as to its application. – David v. Macapagal-Arroyo, supra., cited in Romualdez v. Commission on Elections, G.R. No. 167011, April 30, 2008
The Supreme Court held that the doctrine can only be invoked against that species of legislation that is utterly vague on its face, i.e., that which cannot be clarified either by a saving clause or by construction. – Estrada v. Sandiganbayan, G.R. No. 148560, November 19, 2001
The void-for-vagueness doctrine cannot be used to impugn the validity of a criminal statute using “facial challenge” but it may be used to invalidate a criminal statute “as applied” to a particular defendant.