MANILA, Philippines--The Supreme Court has allowed Sandiganbayan Justice Gregory Ong to keep his seat on the anti-graft court more than a year after it barred his appointment to the high court because of a question on the his citizenship.

In dismissing a petition that sought Ong?s ouster from the Sandiganbayan on account of his alleged Chinese citizenship, the Supreme Court said "any merely private suitor" should not question a magistrate?s authority.

"The rightful authority of a judge, in the full exercise of his public judicial functions, cannot be questioned by any merely private suitor, or by any other, except in the form especially provided by law," said the high court?s ruling, written by Justice Conchita Morales.

"To uphold such action would encourage every disgruntled citizen to resort to the courts, thereby causing incalculable mischief and hindrance to the efficient operation of the governmental machine," the ruling said.

The court also refused to go into lawyer Ferdinand Topacio?s questions on Ong?s being a Chinese citizen or a naturalized Filipino. The Constitution requires judges to be natural-born Filipino citizens.

"Clearly then, it becomes entirely unwarranted at this time to pass upon the citizenship of Ong," the court said.

"The Court cannot, upon the authority of the present petition, determine said question without encroaching on and preempting the proceedings emanating from the RTC case," it added.

Following the high court?s decision in 2007 that barred him from the tribunal, Ong filed a petition with the San Juan Regional Trial Court asking that his birth certificate be corrected to show that he was a natural-born Filipino. The Supreme Court said Topacio?s case in wanting Ong removed from the anti-graft court was different from watchdog Kilosbayan?s case against his being appointed to the Supreme Court.

"The present case is different from Kilosbayan Foundation versus Ermita, given Ong?s actual physical possession and exercise of the functions of the office of an Associate Justice of the Sandiganbayan," the Supreme Court said.

The court said Ong?s possession of the office as Sandiganbayan magistrate sets into motion the de facto doctrine.

It said a de facto officer is "one who is in possession of the office and is discharging its duties under color of authority, and by color of authority is meant that derived from an election or appointment, however irregular or informal, so that the incumbent is not a mere volunteer." "If a person appointed to an office is subsequently declared ineligible therefor, his presumably valid appointment will give him color of title that will confer on him the status of a de facto officer," the court said said.

The court, however, said Ong aside from being found to be a de facto officer may also turn out to be de jure -- "(an) officer who is deemed, in all respects, legally appointed and qualified and whose term of office has not expired." The court also said that Topacio?s petition for certiorari and prohibition against Ong?s continued function as Sandiganbayan justice partakes of a quo warranto petition that is the proper legal remedy to oust a magistrate from office.

"While denominated as a petition for certiorari and prohibition, the petition partakes of the nature of a quo warranto proceeding with respect to Ong, for it effectively seeks to declare null and void his appointment as an Associate Justice of the Sandiganbayan for being unconstitutional," the court said.

"While the petition professes to be one for certiorari and prohibition, petitioner even adverts to a ?quo warranto? aspect of the petition. Being a collateral attack on a public officer?s title, the present petition for certiorari and prohibition must be dismissed," it added.

The court said even if taken as a quo warranto proceeding, the Topacio petition may still be dismissed because a private quo warranto petitioner is required to "show a clear right to the contested office."

"In the present case, petitioner presented no sufficient proof of a clear and indubitable franchise to the office of an Associate Justice of the Sandiganbayan," the court said.