The House of Representatives Electoral Tribunal (HRET) has sole and exclusive jurisdiction over contests relating to the election, returns, and qualifications of members of the House of Representatives once they have been proclaimed, taken their oath, and assumed office; thus, a petition for certiorari before the Supreme Court is an improper remedy to question the qualifications or authority of those who nominated such members.

The case arose from an intra-party leadership dispute within Buhay Hayaan Yumabong (Buhay), a registered party-list organization, concerning who had the authority to nominate its representatives for the May 2007 party-list elections. This dispute occurred against the backdrop of Buhay's previous participation in the 2001 and 2004 elections with Melquiades Robles as its recognized president, and the upcoming 2007 elections where two conflicting Certificates of Nomination were filed with the COMELEC.

• In 1999, Melquiades Robles was elected president of Buhay, a party-list group, with a three-year term without re-election as per Buhay's constitution.
• Robles signed Manifestations of Desire to Participate and Certificates of Nomination for Buhay in the 2001 and 2004 elections, and again for the May 2007 elections on January 26, 2007.
• On March 29, 2007, Robles filed a Certificate of Nomination for Buhay's 2007 nominees.
• On March 27, 2007, petitioner Hans Christian Señeres, claiming to be acting president and secretary-general of Buhay, also filed a Certificate of Nomination for a different set of nominees.
• On April 17, 2007, Señeres filed a Petition to Deny Due Course to Robles' Certificate of Nomination, alleging Robles' term had expired and that Robles, as Acting Administrator of the Light Railway Transport Authority (LRTA), was disqualified from partisan political activity.
• On May 10, 2007, Buhay's National Council expelled Señeres as a party member for filing an unauthorized Certificate of Nomination.
• On July 9 and 18, 2007, COMELEC proclaimed Buhay as a winning party-list organization entitled to three House seats.
• On July 19, 2007, COMELEC en banc issued Resolution E.M. No. 07-043, recognizing Robles as Buhay's president in a hold-over capacity and duly authorized to sign its nomination documents.
• On July 20, 2007, the first three nominees from Robles' list took their oaths of office as Buhay party-list representatives.
• On September 3, 2007, COMELEC, as National Board of Canvassers, issued a Certificate of Proclamation to Buhay and its nominees.

• Melquiades Robles' term as President of BUHAY had expired, rendering his Certificate of Nomination null and void for lack of authority.
• Robles, as Acting Administrator of the LRTA (a government-controlled corporation), was disqualified from being an officer of a political party and from engaging in partisan political activity, such as nominating candidates, under the Constitution and Civil Service Law.
• The COMELEC acted without or in excess of jurisdiction or with grave abuse of discretion in issuing its resolution recognizing Robles as the duly authorized representative of BUHAY.

• (Implicitly, by COMELEC's ruling) Robles was the legitimate president of BUHAY, acting in a hold-over capacity since no party election had been held to replace him.
• (Implicitly, by COMELEC's ruling) Robles' act of signing and submitting the Certificate of Nomination did not constitute prohibited partisan political activity.
• (By Supreme Court's analysis for respondents) The proper remedy for Señeres was a petition for quo warranto before the HRET, not certiorari before the Supreme Court, as Buhay's nominees had already been proclaimed and assumed office.

• Whether the petition for certiorari is the proper remedy to challenge the COMELEC resolution.
• Whether the act of nominating party-list representatives by Robles, an LRTA Administrator, constitutes prohibited partisan political activity.
• Whether Robles had the authority to submit the Certificate of Nomination for BUHAY despite the alleged expiration of his term as president.

• The petition for certiorari is an improper remedy; the proper recourse was a petition for quo warranto before the House of Representatives Electoral Tribunal (HRET) because Buhay's nominees had been proclaimed, taken their oaths, and assumed office, vesting the HRET with sole and exclusive jurisdiction over contests relating to their election, returns, and qualifications.
• Robles' act of submitting a nomination list for BUHAY is not considered electioneering or partisan political activity under Section 79(b) of the Omnibus Election Code, as such acts, when done for enhancing aspirants' chances for nomination by a party, are treated as internal party matters.
• Robles validly acted as President of BUHAY in a "hold-over" capacity because his term expired in October 2002, no election was held to replace him, BUHAY's constitution does not prohibit a hold-over, and corporate officers generally hold over until successors are elected or appointed. His acts as a de facto officer are considered valid.
• Petitioner Señeres is estopped from questioning Robles' authority as BUHAY President, as Robles had signed previous Certificates of Nomination, including one in 2004 which included Señeres as a nominee from which Señeres benefited by earning a seat in Congress.

• Jurisdiction of the House of Representatives Electoral Tribunal (HRET) — The HRET is the sole judge of all contests relating to the election, returns, and qualifications of its respective Members. This jurisdiction begins once a winning candidate has been proclaimed, taken his oath, and assumed office as a Member of the House of Representatives, at which point COMELEC's jurisdiction ends. In this case, since Buhay's nominees were proclaimed and had taken office, any challenge should have been filed with the HRET via a quo warranto petition.
• Partisan Political Activity (Definition under Omnibus Election Code) — Section 79(b) of the Omnibus Election Code defines 'election campaign' or 'partisan political activity' as acts designed to promote the election or defeat of a particular candidate. However, acts performed for the purpose of enhancing the chances of aspirants for nominations for candidacy by a political party are not considered as such. Robles' act of submitting a nomination list was deemed an internal party matter related to nomination, not prohibited partisan political activity for a civil servant.
• Hold-Over Doctrine — Officers and directors of a corporation generally hold over after the expiration of their terms until such time as their successors are elected or appointed. This doctrine, applied by analogy to a party-list organization, means Robles remained President of BUHAY in a hold-over capacity as no successor had been elected or qualified after his term expired, and the party's constitution did not prohibit it.
• De Facto Officer Doctrine — One who continues with the discharge of the functions of an office after the expiration of his or her legal term, without a successor having been appointed or chosen, is commonly regarded as a de facto officer, and their acts are considered valid and effective by fiction of law. Robles' submission of the nomination certificate while in a hold-over capacity was considered a valid act of a de facto officer.
• Estoppel — A principle of equity that precludes a person from going back on his own acts and representations to the prejudice of another whom he has led to rely upon them. Señeres was estopped from questioning Robles' authority because he had previously benefited from Robles' exercise of such authority (nomination in 2004) without objection.

• "The House of Representatives Electoral Tribunal's (HRET's) sole and exclusive jurisdiction over contests relative to the election, returns and qualifications of the members of the House of Representatives 'begins only after a candidate has become a member of the House of Representatives.' Thus, once a winning candidate has been proclaimed, taken his oath, and assumed office as a Member of the House of Representatives, COMELEC's jurisdiction over elections relating to the election, returns, and qualifications ends, and the HRET's own jurisdiction begins."
• "The foregoing enumerated acts if performed for the purpose of enhancing the chances of aspirants for nominations for candidacy to a public office by a political party, agreement, or coalition of parties shall not be considered as election campaign or partisan election activity."
• "As a general rule, officers and directors of a corporation hold over after the expiration of their terms until such time as their successors are elected or appointed."
• "Authorities are almost unanimous that one who continues with the discharge of the functions of an office after the expiration of his or her legal term--no successor having, in the meantime, been appointed or chosen--is commonly regarded as a de facto officer, even where no provision is made by law for his holding over and there is nothing to indicate the contrary. By fiction of law, the acts of such de facto officer are considered valid and effective."

• Lazatin v. House Electoral Tribunal — Cited to elucidate the import of the word "sole" in Art. VI, Sec. 17 of the Constitution, emphasizing the exclusive character of the HRET's jurisdiction.
• Rasul v. COMELEC and Aquino-Oreta — Cited to reiterate that "sole" in the Constitution and Omnibus Election Code underscores the exclusivity of the HRET's jurisdiction over election contests of its members.
• Romualdez-Marcos v. Commission on Elections — Cited for the principle that HRET jurisdiction begins after a candidate becomes a member of the House (proclaimed, taken oath, assumed office).
• Aggabao v. COMELEC — Cited in support of the timing of HRET's jurisdiction.
• Guerrero v. COMELEC — Cited for the definition and requirements of a special civil action for certiorari, and that it is the proper remedy to question final orders of COMELEC in its adjudicatory or quasi-judicial powers, provided there's grave abuse of discretion and no other plain, speedy, adequate remedy.
• Loong v. Commission on Elections — Cited in conjunction with Guerrero regarding certiorari as a remedy for COMELEC decisions.
• Topacio v. Ong — Cited in relation to the de facto officer doctrine, affirming that acts of a de facto officer are valid.
• Stokes v. Malayan Insurance Co., Inc. — Cited for the definition of estoppel as a principle of equity.

• 1987 Constitution, Article VI, Section 17 — Establishes that the Senate and House of Representatives shall each have an Electoral Tribunal which shall be the sole judge of all contests relating to the election, returns, and qualifications of their respective Members. This was central to the Court's finding that HRET had jurisdiction.
• 1987 Constitution, Article IX (B), Section 2 (4) — Prohibits any officer or employee in the civil service from engaging, directly or indirectly, in any electioneering or partisan political campaign. Petitioner invoked this against Robles.
• Omnibus Election Code, Section 79(b) — Defines "election campaign" or "partisan political activity" and explicitly excludes acts performed for enhancing chances of aspirants for nominations by a political party. This was key to ruling Robles' actions were not prohibited.
• Omnibus Election Code, Section 250 — (Referenced via Rasul v. COMELEC) Underscores the exclusivity of the Electoral Tribunal's jurisdiction.
• Omnibus Election Code, Section 26(i) (Should be Sec. 261(i)) — Makes it an election offense for any officer in the civil service to directly or indirectly engage in any partisan political activity. Petitioner invoked this.
• Civil Service Law (Sec. 4, presumably of P.D. 807 or E.O. 292) — Provides that "no officer or employee in the Civil Service x x x shall engage in any partisan political activity." Petitioner cited this.
• Corporation Code, Section 23 — States that directors or trustees shall hold office for one (1) year until their successors are elected and qualified. This was used to support the hold-over doctrine by analogy.
• Revised Rules of the HRET, Rule 14 — Reiterates that the Tribunal shall be the sole judge of all contests relating to the election, returns and qualifications of the Members of the House of Representatives.
• Revised Rules of the HRET, Rule 17 — (Referenced by the Court) Pertains to the filing of a petition for quo warranto within ten (10) days from proclamation, which Señeres failed to do.