I. Defenses based on a Violation of the Due Process Clause


1. Due Process requires that the terms of a penal statute must be sufficiently explicit to inform those who are subject to it what conduct on their part will render them liable to its penalties.

2. The Doctrine that a penal; statute is unconstitutional if it does not reasonably a person on notice as to what the person may not do, or what the person is required to do. As a rule a statue maybe said to be vague when it lacks comprehensible standards that “men of common intelligence must necessarily guess at its meaning and differ as to its application” It is repugnant to the constitution in two aspects: (a) it violates due process for failure to accord persons, especially the parties targeted by it, fair notice of the conduct to avoid and (b) it leaves law enforcers unbridled discretion in carrying out its provisions and become an arbitrary flexing of the government muscle.

3. However an act will be declared void and inoperative on the ground of vagueness and uncertainty, only upon a showing that the defect is such that the courts are unable to determine, within any reasonable degree of certainty, what the legislature intended

Example: An ordinance of the City of Cincinnati that made it illegal for : “three or more persons to assemble on any sidewalk and there conduct themselves in a manner annoying to persons passing by”


1.  A penal statue is unconstitutional if its language is so broad that it unnecessary interferes with the exercise of constitutional rights, even though the purpose is to prohibit activities that the government may constitutionally prohibit.

2. A statute is overbroad where it operates to inhibit the exercise of individual freedoms guaranteed by the constitution, such as the freedom of religion or speech. When it includes within its coverage not only unprotected activity but also activity protected by the constitution.

3. This principle applies more to felonies or offenses which conflict with the freedom of expression  and association such as prosecution for libel, inciting to rebellion or sedition, and violation of the Election Code.

Example: In Adiong s. COMELEC ( 207 SCRA 712) the court declared as void that portion of the Election Code prohibiting the posting of election propaganda in any place-including private vehicles- other than in the designated common poster area.


1. The Penal Statue was not publicized in the manner provided for by the Constitution, such as publication in a newspaper of general circulation or in the Official Gazette. Hence there is no constructive note to the public and the principle that “Ignorantia legis nemenem excusat” will not apply.

II. Defenses Based on the Equal Protection Clause


1. A Penal Law must apply to all persons who are in the same or similar situation

2. A statute nondiscriminatory on its face maybe grossly discriminatory in its operation. Though the law itself be fair on its face and impartial in appearance, yet, if it is applied and administered by public authority with an evil eye and unequal; hand, so as to make unjust and illegal discriminations between persons in similar circumstances, material  to their rights, there is denial of equal justice and is prohibited.

3. However, the prosecution of one guilty person while others equally guilty are not prosecuted, is not, by itself, a denial of the equal protection of the laws. There must be present an element of ”clear and intentional or purposeful discrimination:” on the part of the prosecuting officials.