Vice President Sara Duterte’s camp on Wednesday warned that lowering the Senate’s 16-vote threshold for conviction in her impeachment trial could give the government a way to influence the outcome by targeting senators who may oppose it.

Duterte spokesperson Salvador Paolo Panelo Jr. raised the possibility as the Senate impeachment court heard arguments from retired Supreme Court justices on whether the constitutional two-thirds requirement should be computed from all 24 senators or only those able to participate in the proceedings.

“We should not discuss this without context,” Panelo told reporters.

He questioned why some senators were unable to participate in the trial and whether reducing the number of senators counted in the denominator could create an opportunity for those in power to influence the composition of the impeachment court.

“If the denominator, this 16, can be lowered, you are inviting those in power, the government, to target those senators who they expect will not vote in favor of what they want,” Panelo said.

The Senate impeachment court has been grappling with the issue after Presiding Officer Francis Escudero ruled that 16 votes, or two-thirds of the 24-member Senate, are required to convict Duterte.

Four senators have been unable to participate fully in the proceedings: Jinggoy Estrada and Rodante Marcoleta are detained in connection with separate cases, Ronald dela Rosa is outside the country, and Loren Legarda is on medical leave. 

The court invited retired Chief Justices Reynato Puno and Artemio Panganiban, retired Associate Justice Adolfo Azcuna and retired Chief Justice Hilario Davide Jr. to provide legal guidance on the issue. 

The three on Wednesday questioned whether senators who are unable to participate could remain part of the constitutional denominator, while Azcuna breaks from fellow amici.

The House prosecution has said it will take the position that would make the conviction threshold easier to reach, arguing that it must take a side now that the Senate has scheduled oral arguments on the issue. 

Panelo, however, said Duterte's camp would oppose any reduction of the threshold.

He cited the view of retired Associate Justice Azcuna that the two-thirds requirement was deliberately made difficult to meet to prevent a political faction from easily removing an impeachable official.

“The two-thirds vote was deliberately made difficult so that one faction could not easily use impeachment to remove a government official, an impeachable officer, such as the vice president, who was voted for by 32 million people,” Panelo said.

Panelo said the defense’s participation in the threshold proceedings was ad cautelam, or as a precaution, and did not amount to an admission that the impeachment court had the authority to change the requirement. He said the defense would preserve whatever legal remedies were available to it after the Senate acts.

The Senate is set to hear oral arguments from the prosecution and defense on Sept. 23, after which senator-judges are expected to vote on whether to uphold Escudero’s 16-vote ruling.