The Supreme Court held that each House of Congress has full discretionary authority to determine its rules of proceedings, and the exercise of this power is generally exempt from judicial supervision, except on a clear showing of arbitrary and improvident use constituting a denial of due process; the Senate Committee on Foreign Relations acted within its jurisdiction in investigating the "Moscow incident" due to its potential impact on foreign relations and international obligations.

The case arose from the "Moscow incident" where Gen. Eliseo Dela Paz, then PNP comptroller and part of a Philippine delegation to an INTERPOL conference in Russia, was apprehended at the Moscow airport on October 11, 2008, for failing to declare 105,000 euros found in his luggage, with an additional 45,000 euros in his possession. This led to his detention and the confiscation of the money by Russian authorities, prompting a legislative inquiry by the Philippine Senate.

• On October 6, 2008, a Philippine National Police (PNP) delegation, including Gen. Eliseo D. Dela Paz (then PNP comptroller), arrived in Moscow, Russia, for an INTERPOL General Assembly; Gen. Dela Paz was due to retire on October 9, 2008.
• On October 11, 2008, Gen. Dela Paz was apprehended at the Moscow airport for failing to declare 105,000 euros in his luggage and possessing an additional 45,000 euros.
• Petitioners were detained in Moscow for questioning; Gen. Dela Paz and the PNP delegation were later allowed to return to the Philippines, but the euros were confiscated by the Russian government.
• Gen. Dela Paz arrived in Manila on October 21, 2008, a few days after Mrs. Dela Paz.
• The respondent Senate Committee on Foreign Relations issued subpoenae to petitioners for an investigation into the Moscow incident scheduled for October 23, 2008.
• On October 23, 2008, instead of attending the hearing, petitioners filed a "Challenge to Jurisdiction with Motion to Quash Subpoenae" with the respondent Committee.
• During the hearing, Senator Miriam Defensor-Santiago, Chairperson of the Committee, defended its jurisdiction and verbally commanded the Senate Sergeant-at-Arms to arrest petitioners.
• Subsequently, the Philippine Senate issued a formal written Order of arrest signed by ten senators and approved by the Senate President.
• The Philippine Senate published its Rules of Procedure Governing Inquiries in Aid of Legislation on October 31, 2008.
• On November 15, 2008, Gen. Dela Paz voluntarily appeared before a joint hearing of the respondent Committee and the Senate Blue Ribbon Committee, answering questions.
• During the November 15, 2008 hearing, Senator Santiago granted Gen. Dela Paz's motion to dispense with Mrs. Dela Paz's presence for humanitarian reasons, effectively withdrawing the arrest order against her.

• The respondent Senate Committee on Foreign Relations is devoid of jurisdiction to investigate the Moscow incident because the matter does not involve state-to-state relations as defined by paragraph 12, Section 13, Rule 10 of the Senate Rules of Procedure.
• The respondent Committee violated Senate Rules by issuing a warrant of arrest without the required signatures of the majority of its members.
• The Senate Rules themselves are invalid as a basis for any investigation involving petitioners because they were not published as required by the Constitution.

• The respondent Senate Committee on Foreign Relations, through its Chairperson Senator Santiago, emphatically defended its jurisdiction to investigate the Moscow incident and the legality of its actions, including the issuance of the arrest order.
• The investigation into the Moscow incident falls within the Committee's jurisdiction as it could affect relations between the Philippines and Russia and pertains to Philippine international obligations under conventions like the UN Convention Against Corruption and the UN Convention Against Transnational Organized Crime.
• The actions taken, including the subsequent formal written arrest order, were in accordance with Senate Rules and procedures.

• Whether the respondent Senate Committee on Foreign Relations has jurisdiction to investigate the Moscow incident involving the petitioners.
• Whether the verbal order of arrest issued against the petitioners by the Chairperson of the respondent Committee was valid.
• Whether the Senate Rules of Procedure, allegedly unpublished at the time of the initial actions, could be validly applied.
• Whether the petition for certiorari and prohibition should be granted.

• The petition was dismissed for lack of merit and for being moot and academic.
• The Court affirmed that Section 16(3), Article VI of the Constitution grants each House of Congress full discretionary authority to determine its rules of proceedings, generally exempt from judicial interference, unless there is a clear showing of arbitrary and improvident use of power denying due process; challenging the Senate Committee's jurisdiction is an inquiry into a matter of policy within the Senate's discretion, partaking of a political question.
• The respondent Committee acted within its jurisdiction under Paragraph 12, Section 13, Rule 10 of the Senate Rules, as the Moscow incident could impact Philippine-Russian relations and involves Philippine commitments under international conventions concerning cross-border currency movements.
• The legislative inquiry was to be jointly conducted with the Senate Blue Ribbon Committee, which has broad powers to investigate malfeasance, misfeasance, and nonfeasance in office, applicable to Gen. Dela Paz, a retired PNP general, concerning public funds.
• A formal written Order of arrest, signed by ten senators and approved by the Senate President in accordance with Senate Rules, was subsequently issued, superseding the initial verbal order.
• The Philippine Senate had published its Rules of Procedure Governing Inquiries in Aid of Legislation on October 31, 2008.
• The arrest order became ineffectual as Gen. Dela Paz voluntarily appeared at a subsequent hearing, submitting to the Committees' jurisdiction; the arrest order for Mrs. Dela Paz was effectively withdrawn for humanitarian reasons, rendering these aspects of the petition moot.

• Power of Each House to Determine Rules of Proceedings (Philippine Constitution, Art. VI, Sec. 16(3)) — This provision grants Congress full discretionary authority to formulate, adopt, and promulgate its own rules, generally exempt from judicial supervision except for clear arbitrary use denying due process. Applied here to uphold the Senate's power to define its committees' jurisdiction and procedures, limiting judicial review of such internal matters.
• Political Question Doctrine — This doctrine holds that certain questions, under the Constitution, are to be decided by the people in their sovereign capacity or have been delegated to the legislative or executive branches, and are thus beyond judicial review. Applied here to characterize the challenge to the Senate Committee's jurisdiction as a matter of policy and internal Senate rules, largely non-justiciable.
• Jurisdiction of Senate Committees (Senate Rules of Procedure, Rule 10, Sec. 13, par. 12 & 36) — These rules define the scope of matters that can be investigated by specific Senate committees. Applied here to affirm that the Committee on Foreign Relations (due to potential impact on international relations and obligations) and the Blue Ribbon Committee (due to potential malfeasance involving a public officer and public funds) had jurisdiction over the Moscow incident.
• Moot and Academic Principle — A case becomes moot and academic when it ceases to present a justiciable controversy due to supervening events, rendering a judgment on the merits without practical value. Applied here because Gen. Dela Paz's voluntary appearance at the Senate inquiry and the withdrawal of the arrest order for Mrs. Dela Paz rendered the challenge to the arrest orders ineffectual.

• "Each House shall determine the rules of its proceedings."
• "Thus, it is not for this Court to intervene in what is clearly a question of policy, an issue dependent upon the wisdom, not the legality, of the Senate's action."
• "The Moscow incident could create ripples in the relations between the Philippines and Russia."
• "Furthermore, the matter affects Philippine international obligations."

• Tañada v. Cuenco, 100 Phil. 101 (1957) — Cited to define a political question as one which, under the Constitution, is to be decided by the people in their sovereign capacity, or in regard to which full discretionary authority has been delegated to the legislative or executive branch of the government. This supported the Court's deference to the Senate's internal rules.
• Morrero v. Bocar, 37 O.G. 445 — Cited as authority for the principle that the exercise of Congress's power to determine its rules is generally exempt from judicial supervision, except on a clear showing of arbitrary and improvident use of power constituting a denial of due process.

• Philippine Constitution, Article VI, Section 16(3) — States that "Each House shall determine the rules of its proceedings." This was the primary basis for upholding the Senate's discretionary authority over its internal rules and procedures.
• Rules of Court, Rule 65 — The petition was filed under this rule for Certiorari and Prohibition, alleging grave abuse of discretion by the respondent Senate Committee.
• Senate Rules of Procedure, Rule 10, Section 13, paragraph 12 (Committee on Foreign Relations) — Defines the jurisdiction of the Senate Committee on Foreign Relations. The Court found the Moscow incident fell within this jurisdiction.
• Senate Rules of Procedure, Rule 10, Section 13, paragraph 36 (Blue Ribbon Committee) — Defines the jurisdiction of the Senate Committee on Accountability of Public Officers and Investigations (Blue Ribbon Committee). The Court noted this committee could also investigate Gen. Dela Paz.
• United Nations Convention Against Corruption, Art. 14(2) — Referenced to show that the Moscow incident, involving cross-border movement of substantial cash, relates to Philippine international obligations to implement measures for detecting and monitoring such movements.
• United Nations Convention Against Transnational Organized Crime, Art. 7(1) & 7(2) — Referenced to show that the Moscow incident also relates to Philippine obligations under this convention to deter and detect money laundering and monitor cross-border cash movements.