Void for vagueness

"These cases require us to consider the validity of the Partial-Birth Abortion Ban Act of 2003 (Act), 18 U.S.C. § 1531 . . . a federal statute regulating abortion procedures."

"The Act punishes 'knowingly perform[ing]' a 'partial-birth abortion.'  § 1531(a) . . . .  It defines the unlawful abortion in explicit terms.  § 1531(b)(1)."

"Respondents contend the language described above is indeterminate, and they thus argue the Act is unconstitutionally vague on its face.  As generally stated, the void-for-vagueness doctrine requires that a penal statute define the criminal offense with sufficient definiteness that ordinary people can understand what conduct is prohibited and in a manner that does not encourage arbitrary and discriminatory enforcement.  The Act satisfies both requirements."

"The Act provides doctors of ordinary intelligence a reasonable opportunity to know what is prohibited.  Indeed, it sets forth relatively clear guidelines as to prohibited conduct and provides objective criteria to evaluate whether a doctor has performed a prohibited procedure.  Unlike the statutory language in Stenberg that prohibited the delivery of a ‘substantial portion’ of the fetus - where a doctor might question how much of the fetus is a substantial portion - [this] Act defines the line between potentially criminal conduct on the one hand and lawful abortion on the other.  Doctors . . . will know that if they do not deliver a living fetus to an anatomical landmark they will not face criminal liability."