Republic Act No. 7080, the Plunder Law, as amended by RA 7659, is constitutional and does not suffer from the vice of vagueness, nor does it violate the accused's rights to due process and to be informed of the nature and cause of the accusation. The law provides ascertainable standards and well-defined parameters for the crime of plunder.

Petitioner Joseph Ejercito Estrada, the highest-ranking official to be prosecuted under RA 7080 (Plunder Law), faced charges before the Sandiganbayan for allegedly amassing ill-gotten wealth during his presidency. This case arose from his efforts to quash the Information against him by challenging the constitutionality of the Plunder Law itself, which defines and penalizes the crime of plunder.

• Petitioner Joseph Ejercito Estrada, former President of the Philippines, was charged with plunder under RA 7080, as amended by RA 7659, before the Sandiganbayan in Criminal Case No. 26558.
• The Amended Information alleged that Estrada, during his presidency from June 1998 to January 2001, by himself or in conspiracy with others, willfully, unlawfully, and criminally amassed ill-gotten wealth amounting to P4,097,804,173.17.
• The alleged ill-gotten wealth was acquired through a combination or series of overt or criminal acts, including: (a) receiving money from illegal gambling; (b) diverting, receiving, or misusing public funds from tobacco excise tax shares; (c) directing government financial institutions (GSIS and SSS) to purchase Belle Corporation shares and receiving commissions therefrom, deposited under the account name "Jose Velarde"; and (d) unjustly enriching himself from commissions, gifts, shares, percentages, or kickbacks deposited under the account name "Jose Velarde" at Equitable-PCI Bank.
• Petitioner moved to quash the Information, arguing that RA 7080 is unconstitutional for vagueness, violates due process, and that the Information charged more than one offense. The Sandiganbayan denied the Motion to Quash.

• The Plunder Law (RA 7080) is unconstitutional for being impermissibly vague and overbroad, particularly in its use of terms like "combination," "series," and "pattern" without statutory definitions, thereby denying the accused the right to be informed of the nature and cause of the accusation and violating due process.
• Section 4 of the Plunder Law, the "Rule of Evidence," dispenses with the "reasonable doubt" standard for proving predicate crimes and violates the accused's right to due process by not requiring proof of each and every criminal act.
• The Plunder Law abolishes the element of mens rea in crimes that are mala in se under the Revised Penal Code, effectively converting them into mala prohibita, which is beyond the power of Congress and violates due process.
• The term "pattern" in Section 4 is a substantive element of the crime but is not defined, adding to the law's vagueness.

• The Plunder Law contains ascertainable standards and well-defined parameters, making it constitutionally valid. Section 2 explicitly describes the acts, conduct, and conditions required or forbidden.
• The terms "combination" and "series" should be understood in their popular meanings, as evident from legislative deliberations, referring to at least two different types of acts or two or more instances of the same act, respectively.
• The term "pattern" is sufficiently defined in Section 4 in relation to Section 1(d) and Section 2, requiring a common purpose to amass ill-gotten wealth through an overall unlawful scheme or conspiracy.
• The void-for-vagueness and overbreadth doctrines are generally inapplicable to penal statutes and are primarily relevant to free speech cases; a facial challenge is inappropriate.
• Section 4 of the Plunder Law does not dispense with proof beyond reasonable doubt for the elements of plunder; it only clarifies that not every single predicate act alleged needs to be proven, as long as a pattern indicative of the overall scheme is established beyond reasonable doubt.
• Plunder is malum in se, requiring criminal intent, which is evident from the law's provision for mitigating and extenuating circumstances and the use of terms like "willfully, unlawfully and criminally" in the Information.
• The legislative declaration that plunder is a heinous crime (RA 7659) implies it is malum in se.

• Whether Republic Act No. 7080 (Plunder Law) is unconstitutional for being vague.
• Whether the Plunder Law requires less evidence for proving the predicate crimes of plunder and therefore violates the rights of the accused to due process.
• Whether Plunder as defined in RA 7080 is a malum prohibitum, and if so, whether it is within the power of Congress to so classify it.

• The Plunder Law (RA 7080) is CONSTITUTIONAL. The petition to declare the law unconstitutional is DISMISSED for lack of merit.
• The Plunder Law is not vague. It contains ascertainable standards and well-defined parameters. Section 2 sufficiently describes the acts, conduct, and conditions required or forbidden. The terms "combination" and "series" are to be understood in their ordinary and popular meanings, clarified by legislative intent, referring to at least two different acts or at least two instances of the same act, respectively. The term "pattern" is adequately defined by Section 4 in relation to Sections 1(d) and 2, referring to a pattern of overt or criminal acts directed towards amassing ill-gotten wealth through an overall unlawful scheme or conspiracy.
• The void-for-vagueness and overbreadth doctrines are not applicable for a facial challenge to penal statutes like the Plunder Law, which do not primarily regulate speech. Such doctrines are "manifestly strong medicine" to be used sparingly.
• Section 4 of the Plunder Law does not violate the due process right by lowering the quantum of proof. The prosecution must still prove beyond reasonable doubt the elements of plunder, including a pattern of overt or criminal acts indicative of the overall unlawful scheme. It does not require proof of each and every predicate act alleged, but a sufficient number to establish the pattern and the aggregate amount. "Pattern" is not an essential element of plunder but a way of proving the conspiracy or scheme.
• Plunder is a malum in se crime, requiring proof of criminal intent (mens rea). The constitutive crimes are generally mala in se. The law's provision for mitigating and extenuating circumstances under the Revised Penal Code indicates that mens rea is an element. The legislative declaration of plunder as a heinous crime further supports its malum in se nature.

• Presumption of Constitutionality — Legislative acts are presumed to be in harmony with the Constitution. The party challenging the statute bears the heavy burden of proving its unconstitutionality beyond any tinge of doubt. Applied in upholding RA 7080, as petitioner failed to overcome this presumption.
• Void-for-Vagueness Doctrine — A statute is void if it lacks comprehensible standards that persons of common intelligence must necessarily guess at its meaning and differ in its application, thus violating due process by failing to provide fair notice. The Court found RA 7080 not vague, as its terms provide reasonable certainty. This doctrine is generally not applicable for facial challenges to penal statutes unless they involve free speech.
• Overbreadth Doctrine — A statute is overbroad if it sweeps unnecessarily broadly and thereby invades the area of protected freedoms (typically free speech). The Court held this doctrine inapplicable for a facial challenge to the Plunder Law as it is a penal statute not primarily regulating speech.
• Statutory Construction (Plain Meaning Rule / Legislative Intent) — Words of a statute are interpreted in their natural, plain, and ordinary acceptation unless the legislature intended a technical meaning. Legislative deliberations can be consulted to ascertain intent. Applied to interpret "combination," "series," and "pattern" in RA 7080.
• Mens Rea in Mala in Se Crimes — Acts that are inherently immoral (mala in se) require criminal intent. The Court affirmed that plunder is malum in se, and its predicate crimes are mostly mala in se, thus requiring proof of criminal intent.
• Separability Clause — If a provision of an Act is held invalid, the remaining provisions shall not be affected if they can stand independently. Mentioned in the context that even if Section 4 were flawed (which it was not found to be), the rest of RA 7080 could potentially survive.
• Facial Challenge vs. As-Applied Challenge — A facial challenge asserts that a law is unconstitutional on its face, while an as-applied challenge asserts unconstitutionality based on its application to a specific set of facts. The Court emphasized that penal statutes are generally challenged "as applied," not facially, unless they impinge on free speech.

• "To doubt is to sustain." (Quoting Justice Malcolm, emphasizing the high bar for overcoming the presumption of constitutionality).
• "As long as the law affords some comprehensible guide or rule that would inform those who are subject to it what conduct would render them liable to its penalties, its validity will be sustained."
• "A statute is not rendered uncertain and void merely because general terms are used therein, or because of the employment of terms without defining them; much less do we have to define every word we use."
• "[T]he `vagueness' doctrine merely requires a reasonable degree of certainty for the statute to be upheld - not absolute precision or mathematical exactitude..."
• "[O]n its face' invalidation of statutes has been described as 'manifestly strong medicine,' to be employed 'sparingly and only as a last resort,' and is generally disfavored."
• "The Plunder Law, indeed, is a living testament to the will of the legislature to ultimately eradicate this scourge and thus secure society against the avarice and other venalities in public office."

• La Union Credit Cooperative, Inc. v. Yaranon — Cited to support the principle that courts will avoid ruling on constitutionality if a case can be decided on other grounds, and that the presumption of constitutionality is strong.
• Yu Cong Eng v. Trinidad — Referenced for the principle that "To doubt is to sustain" regarding the presumption of constitutionality.
• Gallego v. Sandiganbayan — Cited as a parallel case where a challenge to the vagueness of a term ("unwarranted" in the Anti-Graft Law) was dismissed, showing judicial reluctance to void statutes for uncertainty unless absolutely necessary.
• People v. Echegaray — Referenced for its holding that RA 7659 (which included plunder among heinous crimes) is constitutionally valid, and for its discussion on the nature of heinous crimes, supporting the view that plunder is malum in se.
• Broadrick v. Oklahoma — Cited in Justice Mendoza's adopted observations to explain that overbreadth claims are curtailed when invoked against ordinary criminal laws, and that facial challenges are most difficult to mount.
• United States v. Salerno — Referenced in Justice Mendoza's adopted observations for the principle that a facial challenge to a legislative act requires the challenger to establish that no set of circumstances exists under which the Act would be valid.
• Connally v. General Constr. Co. — Cited for the classic formulation of the void-for-vagueness doctrine.
• Younger v. Harris — Quoted in Justice Mendoza's adopted observations on why "on its face" invalidation of statutes is generally disfavored and an inappropriate task for the judiciary.

• Republic Act No. 7080 (Plunder Law), Section 1(d) — Defines "ill-gotten wealth" and enumerates the means by which it can be acquired. Its terms ("combination," "series") were central to the vagueness challenge.
• Republic Act No. 7080 (Plunder Law), Section 2 — Defines the crime of plunder, specifies the offender (public officer), the act (amassing ill-gotten wealth of at least P50 million through a combination or series of overt/criminal acts), and the penalty. Its clarity was upheld.
• Republic Act No. 7080 (Plunder Law), Section 4 — "Rule of Evidence" stating it's not necessary to prove every criminal act if a "pattern of overt or criminal acts indicative of the overall unlawful scheme or conspiracy" is established. Its interpretation was key to the due process challenge. The Court held it does not lower the quantum of proof but clarifies the method of proving the scheme.
• Republic Act No. 7080 (Plunder Law), Section 7 — Separability clause. Mentioned as a safeguard for the law's validity even if a part were found unconstitutional.
• Republic Act No. 7659 — Amended RA 7080, notably including plunder among heinous crimes punishable by death. Its declaration of plunder as heinous was used to argue its malum in se nature.
• Revised Penal Code — Referenced for principles like mens rea, mitigating/extenuating circumstances, and penalties for predicate crimes. Its application to Plunder Law (for penalties and circumstances) was cited to support that plunder is malum in se.

• Justice Vicente V. Mendoza — His observations during deliberations, adopted by the ponente, extensively argued against a facial challenge to the Plunder Law, asserting that void-for-vagueness and overbreadth doctrines are special tools for free speech cases and inappropriate for penal statutes. He maintained that plunder is malum in se, requiring proof of criminal intent, and that Section 4 does not eliminate the need to prove predicate acts but rather addresses proof of conspiracy. He also detailed how "combination" and "series" are understood from legislative records.
• Justice Artemio V. Panganiban — Concurred, emphasizing that RA 7080 is not vague if its terms are understood through statutory construction using legislative intent. He argued that "combination" means joining at least two dissimilar acts, and "series" means a repetition of the same act at least twice. He found Section 4 to be a rule of evidence not lowering the quantum of proof but requiring proof of a "pattern" beyond reasonable doubt, which itself entails proving the constituent acts beyond reasonable doubt. He also affirmed Congress's power to enact mala prohibita laws, though he agreed plunder is malum in se.
• Justices Puno and Vitug — Concurred and joined Justice Mendoza's concurring opinion.
• Chief Justice Davide, Jr., Justices Melo and Quisumbing — Joined Justice Mendoza's concurring opinion.
• Justices Buena and De Leon, Jr. — Concurred with the main opinion.

• Justice Santiago M. Kapunan — Argued RA 7080 is unconstitutional for vagueness due to undefined terms like "combination," "series," and "pattern," violating due process. He contended that Section 4 effectively eliminates mens rea for component crimes and lowers the quantum of proof. He believed that the law's ambiguity makes it susceptible to arbitrary enforcement and that even men steeped in law find difficulty in understanding plunder. He highlighted that some acts under Section 1(d) (like acquiring stocks or establishing monopolies) are not inherently criminal.
• Justice Bernardo P. Pardo — Voted to grant the petition on the ground of multiplicity of offenses charged in the amended information, finding it unnecessary to rule on the law's constitutionality but stated that Section 4 must be interpreted as requiring proof beyond reasonable doubt for all elements, including component crimes, otherwise it would be unconstitutional.
• Justice Consuelo Ynares-Santiago — Argued that the Plunder Law is unconstitutionally vague and overbroad, violating due process and the right to be informed. She stated that the law's terms are not susceptible to ready or clear understanding, leading to arbitrary enforcement, and that criminal intent (mens rea) for mala in se predicate crimes is effectively abolished.
• Justice Angelina Sandoval-Gutierrez — Argued RA 7080 is unconstitutional as Section 4 lessens the burden of prosecution by dispensing with proof of essential elements (the specific criminal acts), violating due process. She contended that treating criminal acts merely as "means" allows conviction even if Justices don't unanimously agree on which specific acts were committed. She also found "pattern," "combination," and "series" vague and that the law improperly converts mala in se offenses into mala prohibita.