The Tripartite Agreement for Joint Marine Seismic Undertaking (JMSU) is unconstitutional and void because it allows wholly-owned foreign corporations to participate in the exploration of the Philippines' natural resources (petroleum) without complying with the safeguards provided in Section 2, Article XII of the 1987 Constitution, particularly the requirement that such agreements be entered into by the President and that the State maintain full control and supervision.

The case arose from the signing of the Tripartite Agreement for Joint Marine Seismic Undertaking (JMSU) on March 14, 2005, by the Philippine National Oil Company (PNOC), China National Offshore Oil Corporation (CNOOC), and Vietnam Oil and Gas Corporation (PETROVIETNAM). The JMSU aimed to conduct joint research of petroleum resource potential in a 142,886 square kilometer area in the South China Sea, designated as a "pre-exploration activity," with the stated goal of transforming the South China Sea into an area of peace, stability, cooperation, and development. This agreement became controversial due to its implications on national sovereignty and the constitutional provisions governing the exploration and utilization of natural resources within Philippine territory and its exclusive economic zone (EEZ).

• On March 14, 2005, PNOC (Philippines), CNOOC (China), and PETROVIETNAM (Vietnam), all state-owned oil companies, signed the Joint Marine Seismic Undertaking (JMSU) in Manila, with a term of three years.
• The JMSU's stated purpose was to engage in a joint research of petroleum resource potential in a 142,886 square kilometer area of the South China Sea, described as a "pre-exploration activity."
• Article 4.1 of the JMSU authorized the collection and processing of 2D and/or 3D seismic lines within the Agreement Area.
• A Joint Operating Committee (JOC) was to be established for the proper performance of the joint activity, with each party appointing three representatives and having effective and equal participation.
• The JMSU included a confidentiality clause, restricting disclosure of information without written consent of all Parties.
• The JMSU's effectivity was contingent upon approval from the respective governments of the Parties.
• The Department of Energy (DOE) Secretary Raphael P.M. Lotilla allegedly issued a six-month permit on June 5, 2005, to PNOC Exploration Corporation (PNOC-EC), assignee of PNOC, constituting the Philippine Government's approval.
• The JMSU commenced implementation on July 1, 2005, for a term until July 1, 2008. The first permit expired on December 10, 2005, and a second six-month permit was allegedly issued on October 4, 2007.
• On May 21, 2008, petitioners, as legislators, taxpayers, and citizens, filed the petition assailing the JMSU's constitutionality.
• The JMSU expired on June 30, 2008, during the pendency of the petition.
• Petitioners alleged the Agreement Area is within the Philippines' EEZ and includes almost 80% of the Spratly Group of Islands, a claim not disputed by respondents.

• The JMSU is unconstitutional as it allows large-scale exploration of petroleum and other mineral oils by wholly foreign-owned corporations in Philippine archipelagic waters, territorial sea, and exclusive economic zone (EEZ), violating Section 2(1), Article XII of the 1987 Constitution.
• The JMSU is not covered by any permissible undertakings for the exploration, development, and utilization (EDU) of natural resources under the 1987 Constitution.
• Respondents PGMA and ES Ermita committed grave abuse of discretion by authorizing and tolerating the JMSU's execution and implementation.
• The DFA Secretary committed grave abuse of discretion by participating in the planning, negotiations, and preparation leading to the JMSU's signing and approval.
• The DOE Secretary committed grave abuse of discretion by issuing a permit to PNOC-EC, which constituted the Philippine Government's approval of the JMSU.
• PNOC committed grave abuse of discretion by entering into an agreement with foreign-owned corporations for large-scale exploration within Philippine-owned territory.
• PNOC-EC committed grave abuse of discretion by being an assignee of PNOC's rights and obligations under the JMSU.
• Direct recourse to the Supreme Court is justified due to serious constitutional questions, repercussions on national economy and sovereignty, and the novelty of the issues.
• The issue of mootness due to JMSU expiration should be overcome by exceptions, such as grave constitutional violation and capability of repetition.
• Seismic work, survey, or mapping is an integral part of exploration, not mere pre-exploration activity.
• The joint ownership of information acquired under the JMSU (Article 11.2) effectively concedes the Republic's dominion over its natural resources.

• President Gloria Macapagal-Arroyo (PGMA) is immune from suit and should be excluded as a respondent.
• The President and cabinet members are not liable as they are not parties to the JMSU, which was executed by PNOC, a GOCC with a separate personality.
• The doctrine of qualified political agency does not apply.
• The petition fails to make a case for certiorari and prohibition as the execution of a commercial contract is executive and discretionary.
• The petition presents no justiciable controversy because the JMSU expired on June 30, 2008, and has not been renewed.
• The issues raised are factual and require evidence presentation, improper for certiorari and prohibition; the proper remedy is an ordinary civil action for annulment of contract in the RTC.
• The JMSU involves pre-exploration activities, not the exploration, development, and utilization (EDU) of natural resources contemplated by Section 2, Article XII of the Constitution.
• Assuming the JMSU is attributable to the State, the pre-exploration activities comply with the constitutional requirement of full control and supervision by the State.
• The modalities prescribed in the 1987 Constitution for EDU of natural resources do not apply to the JMSU.
• The JMSU is similar to a Memorandum of Understanding (MOU) with the Government of Australia for seismic data gathering, which the DOJ opined was a pre-exploration activity not covered by constitutional limitations.
• Sharing scientific data generated from an international cooperative effort does not diminish the State's full control and supervision over its resources or impinge on ownership of natural resources.
• The JMSU is an exercise of the State's power of auto-limitation under international law and part of cooperative efforts for marine scientific research under UNCLOS.

• Whether President Gloria Macapagal-Arroyo may be impleaded as a respondent.
• Whether writs of certiorari and prohibition are proper to assail the constitutionality of the JMSU.
• Whether the doctrine of hierarchy of courts was violated by the direct filing of the petition with the Supreme Court.
• Whether the requisites for judicial review are present (actual case or controversy, legal standing, raised at earliest opportunity, lis mota).
• Whether the JMSU is unconstitutional for violating Section 2, Article XII of the 1987 Philippine Constitution.

• President Gloria Macapagal-Arroyo (PGMA) was improperly impleaded as a respondent due to presidential immunity from suit during her tenure.
• Writs of certiorari and prohibition under the Court's expanded jurisdiction are proper remedies to assail the constitutionality of the JMSU and determine grave abuse of discretion by respondents.
• Direct recourse to the Supreme Court is justified because the case involves genuine issues of constitutionality and pure questions of law, specifically the interpretation of "exploration" under the Constitution.
• All requisites for judicial review are present: (1) an actual case or controversy exists despite the JMSU's expiration due to exceptions to the mootness doctrine (grave constitutional violation, paramount public interest, need to formulate guiding principles, capability of repetition); (2) petitioners have legal standing as legislators (infringement of congressional power over natural resources), taxpayers (illegal disbursement of PNOC funds), and concerned citizens (transcendental importance); (3) the constitutionality question was raised at the earliest opportunity (first instance in this direct petition); and (4) the constitutionality of the JMSU is the very lis mota of the case.
• The JMSU involves "exploration" of petroleum resources, as its objective was to conduct joint research of petroleum resource potential using seismic surveys, which fall under both ordinary and technical definitions of exploration. The designation as "pre-exploration activity" is immaterial.
• The JMSU is unconstitutional because it allows wholly-owned foreign corporations (CNOOC and PETROVIETNAM) to participate in the exploration of Philippine petroleum resources without complying with any of the four modes permitted by Section 2, Article XII of the 1987 Constitution.
• The JMSU does not qualify as the fourth mode (agreements with foreign-owned corporations involving technical or financial assistance) because it involves no such assistance, was not signed by the President, and was not reported to Congress, failing the safeguards established in La Bugal-B'laan.
• The State, through PNOC, did not maintain full control and supervision over the exploration activities, as evidenced by the joint ownership of all data and information acquired, requiring consent from foreign parties for disclosure, and placing the Parties' rights on an equal basis.
• The PNOC has no power to enter into contracts involving the exploration of the country's petroleum resources with foreign-owned corporations; this power is expressly reserved to the President under Section 2, Article XII of the Constitution and cannot be delegated.
• The State's consent for auto-limitation was wanting as the President did not personally sign the JMSU, and it was not concurred in by the Senate as an international agreement.

• Presidential Immunity from Suit — The President cannot be sued while holding office to ensure the exercise of presidential duties is free from distractions. Applied here to drop PGMA as a respondent as she was the incumbent president when the petition was filed.
• Expanded Certiorari Jurisdiction (Art. VIII, Sec. 1, par. 2, 1987 Constitution) — The Supreme Court's power to review acts of any branch or instrumentality of government for grave abuse of discretion amounting to lack or excess of jurisdiction, even if not exercising judicial, quasi-judicial, or ministerial functions. Applied here to justify certiorari and prohibition as proper remedies to assail the JMSU's constitutionality.
• Hierarchy of Courts — General rule that petitions for extraordinary writs should first be filed in lower-ranked courts. Applied here by recognizing exceptions, allowing direct recourse to the Supreme Court due to genuine issues of constitutionality and the case involving a pure question of law.
• Requisites of Judicial Review — Conditions for the exercise of the power of judicial review: (1) actual case or controversy; (2) legal standing of the challenger; (3) question of constitutionality raised at the earliest possible opportunity; (4) constitutional question is the very lis mota of the case. The Court found all requisites present.
• Actual Case or Controversy (and Mootness Doctrine Exceptions) — A conflict of legal rights susceptible to judicial resolution, not conjectural or moot. A case becomes moot if supervening events make a declaration thereon of no practical value. Exceptions allow deciding moot cases if there is: (1) grave constitutional violation; (2) exceptional character and paramount public interest; (3) need to formulate controlling principles; (4) capability of repetition yet evading review. All four exceptions were found applicable to the JMSU's expiration.
• Locus Standi (Legal Standing) — The right of appearance in court on a given question, requiring direct injury or meeting criteria for non-traditional suitors (taxpayers, voters, concerned citizens, legislators). Petitioners were granted standing as legislators (usurpation of congressional power over natural resources), taxpayers (illegal disbursement of public funds by PNOC), and concerned citizens (transcendental importance).
• Verba Legis (Plain Meaning Rule) — Constitutional construction principle that words used in the Constitution must be given their ordinary meaning, except for technical terms. Applied to define "exploration" by its ordinary and technical (Petroleum Act of 1949, Philippine Mining Act) meanings.
• Regalian Doctrine (Jura Regalia) — Principle that all natural resources are owned by the State. Embodied in the first sentence of Section 2, Article XII of the Constitution and served as the foundational basis for analyzing the State's rights over petroleum resources.
• State's Power of Auto-limitation — A state may, by its consent, submit to a restriction of its sovereign rights. The Court found this inapplicable as the President did not personally sign the JMSU, thus State consent was wanting.
• Doctrine of Qualified Political Agency — Acts of department secretaries performed in the regular course of business are presumptively acts of the Chief Executive. The Court stated this doctrine does not apply to the President's power to enter into contracts for EDU of natural resources with foreign corporations, as this power is expressly reserved to the President.

• "The Court also has the duty to formulate guiding and controlling constitutional principles, precepts, doctrines, or rules. It has the symbolic function of educating bench and bar on the extent of protection given by constitutional guarantees."
• "Thus, exploration, whether used in the ordinary or technical sense pertains to a search or discovery of something."
• "That the Parties designated the joint research as a 'pre-exploration activity' is of no moment. Such designation does not detract from the fact that the intent and aim of the agreement is to discover petroleum which is tantamount to 'exploration.'"
• "In fine, the JMSU is unconstitutional for allowing wholly-owned foreign corporations to participate in the exploration of the country's natural resources without observing the safeguards provided in Section 2, Article XII of the 1987 Constitution."
• "[T]he PNOC bargained away the State's supposed full control of all the information acquired from the seismic survey as the consent of CNOOC and PETROVIETNAM would be necessary before any information derived therefrom may be disclosed."

• David v. Macapagal-Arroyo — Cited for explaining presidential immunity from suit and for the application of exceptions to the moot and academic principle.
• De Lima v. Duterte — Cited to reinforce that presidential immunity is not dependent on the nature of the suit but aims to prevent distraction from presidential duties.
• Araullo v. Aquino III — Cited for distinguishing ordinary certiorari from expanded certiorari jurisdiction and for applying exceptions to the mootness doctrine regarding the DAP.
• The Diocese of Bacolod v. Commission on Elections — Cited for summarizing reasons allowing direct recourse to the Supreme Court, bypassing the hierarchy of courts.
• Gios-Samar, Inc. v. Department of Transportation and Communications — Clarified that direct recourse to the Supreme Court is permissible when the issue involves a pure question of law.
• Malixi v. Baltazar — Cited for the rationale behind requiring certified true copies in certiorari petitions (though excused here).
• Resident Marine Mammals of the Protected Seascape Tañon Strait v. Reyes — Cited for deciding a moot case involving a service contract for petroleum exploration due to exceptions, and for the principle that the President must be the signatory to such contracts. Also cited for the non-delegability of the President's power to enter into such agreements.
• Chavez v. Public Estates Authority — Cited for the principle that supervening events cannot prevent the Court from deciding a case involving a grave constitutional violation.
• Miners Association of the Phils., Inc. v. Factoran, Jr. — Cited to establish that EDU of natural resources is vital to public interest.
• La Bugal-B'laan Tribal Association, Inc. v. Ramos — Heavily relied upon for establishing legislators' standing in natural resource cases, for interpreting the fourth mode of EDU under Sec. 2, Art. XII (that FTAAs encompass service contracts with safeguards), and for the requirements (President as signatory, report to Congress) for such agreements with foreign corporations.
• Francisco, Jr. v. House of Representatives — Cited for determinants of transcendental importance for legal standing.
• Apex Mining Co. Inc. v. Southeast Mindanao Gold Mining Corporation — Cited to explain that an exploration permit does not automatically grant the right to extract minerals and to differentiate exploration from development and exploitation.
• Angara v. The Electoral Commission — Cited for the Supreme Court's role as the final arbiter in interpreting the Constitution and checking other government departments.

• 1987 Philippine Constitution, Article XII, Section 2 — The central provision at issue, detailing State ownership of natural resources, the requirement of full State control and supervision over their EDU, and the permissible modes for such EDU, including agreements with foreign corporations for large-scale exploration signed by the President. This section was the primary basis for declaring the JMSU unconstitutional.
• 1987 Philippine Constitution, Article VIII, Section 1, paragraph 2 — Defines judicial power, including the expanded certiorari jurisdiction of courts to review acts of any branch of government for grave abuse of discretion. This was invoked to affirm the propriety of the petition.
• 1987 Philippine Constitution, Article VII, Section 21 — Requires Senate concurrence for treaties or international agreements. Referenced in relation to the argument that if JMSU were treated as an international agreement, it lacked Senate concurrence.
• Rules of Court, Rule 65 — Governs petitions for certiorari and prohibition. The Court discussed its application in the context of expanded certiorari jurisdiction.
• Republic Act No. 7942 (Philippine Mining Act of 1995), Section 3(q) — Provided a technical definition of "exploration" for mineral resources, used by the Court to support its finding that the JMSU involved exploration.
• Republic Act No. 387 (Petroleum Act of 1949), Article 38 — Provided a technical definition of "exploration" for petroleum, used by the Court to determine that the activities under JMSU constituted exploration.
• Presidential Decree No. 87 (Oil Exploration and Development Act of 1972) — The general law on exploration, development, and utilization of indigenous petroleum. Referenced to define "service contract" and to show JMSU was not such a contract.
• United Nations Convention on the Law of the Sea (UNCLOS), Article 239 — Referenced by respondents in arguing JMSU was part of cooperative marine scientific research, an argument not fully adopted by the Court in its reasoning for unconstitutionality.

• Chief Justice Alexander G. Gesmundo — Concurred with the ponencia, emphasizing that the JMSU is unconstitutional because it was not entered into by the President as required by Article XII, Section 2 of the Constitution for agreements with foreign-owned corporations involving large-scale exploration of natural resources. He reiterated that this authority is vested solely in the President and cannot be delegated.
• Senior Associate Justice Marvic M.V.F. Leonen — Concurred, stating the JMSU gravely violated Article XII, Section 2. He elaborated on the State's sovereignty and jurisdiction over its national territory and natural resources, emphasizing the public trust doctrine. He agreed that information from exploration activities is exclusively reserved for Filipinos and cannot be jointly owned with foreign corporations, and that the President is the only authorized signatory for such agreements. He also opined that the agreement area should be referred to as within the West Philippine Sea.

• Justice Amy C. Lazaro-Javier — Dissented, arguing that the petition should be dismissed due to procedural infirmities, primarily the violation of the doctrine of hierarchy of courts (as there were unmistakable questions of fact requiring evidence) and mootness (JMSU had expired). She contended that the Court should not decide cases based on online news articles and hearsay. She also characterized the JMSU as predominantly a foreign relations matter requiring judicial deference, and that "exploration" under Article XII, Section 2 should be interpreted to involve extraction, which the JMSU did not intend.
• Justice Rodil V. Zalameda — Dissented, arguing that the case should be dismissed for being moot and academic as the JMSU had long expired, and the exceptions to the mootness rule were not convincingly met. He highlighted the uncertainty regarding the exact nature and location of the activities under the JMSU due to lack of a certified copy and fully litigated facts, making a constitutional ruling speculative. He emphasized the importance of the actual case or controversy requirement and judicial restraint.