MANILA — A law expert on Wednesday said Vice-President Leni Robredo was merely exercising freedom of speech when she raised concerns about the government’s war on illegal drugs in a video played at a side event of the 60th Session of the United Nations Commission on Narcotic Drugs.

Father Ranhilio Aquino, dean of the San Beda Graduate School of Law, told ABS-CBN News he “did not find anything offensive” in what Robredo said in the video, but he noted it’s up to the House of Representatives to decide whether the planned impeachment case against her should be dismissed or not.

“It’s up to the lower house. The Constitution leaves it to the lower house,” Aquino said.

Robredo drew flak from aides and supporters of President Rodrigo Duterte after she made claims of irregularities in the government’s illegal-drugs campaign in a video played at one of the side events of the annual meeting.

In the video, Robredo revealed the so-called "palit-ulo" scheme, in which authorities would supposedly take a family member instead in case the original person on the drug list cannot be found.

"They told us of the 'palit-ulo scheme' which literally means 'exchange heads,' where the wife or husband or relative of a person in a so-called drug list will be taken if the person himself could not be found," Robredo said.

'TRUTH-TELLING NOT AN IMPEACHABLE OFFENSE'

For an impeachment complaint to prosper in the House of Representatives, the lower chamber must determine it to be sufficient in form and substance. The votes of at least one-third of the members of the House are also needed.

In threatening to lead an impeachment complaint against Robredo, House Speaker Pantaleon Alvarez said the vice president committed treason by tarnishing the country's reputation before the international community.

Robredo, through legal adviser Barry Gutierrez, said the impeachment threat was baseless, arguing that “truth-telling is not an impeachable offense.”

Loyalists of former President Ferdinand Marcos, whose son Ferdinand Jr. lost to Robredo in the vice-presidential race, then asked Alvarez to endorse their own impeachment complaint.

‘YOU DO THE MATH’

Meanwhile, Aquino refused to speculate how the impeachment complaint against Duterte, filed just before the Congress went on a break, would play out.

“I don’t like to speculate but just look at the figures. For an impeachment [complaint] to succeed they must vote for the articles of impeachment,” he said.

“You do the math.”

The impeachment complaint on Duterte, filed by Magdalo party-list Rep. Gary Alejano, accuses the president of culpable violation of the Constitution, betrayal of public trust, graft and corruption, bribery and other high crimes.

Duterte's allies and political analysts say the complaint has a slim chance of hurdling the lower chamber, but Alejano and fellow Magdalo member Senator Antonio Trillanes IV are not losing hope.

Alejano's complaint centers on the thousands of deaths linked to the government’s war on illegal drugs and Duterte’s alleged role in the Davao Death Squad.

The Magdalo group is also mulling a supplemental complaint against Duterte over his much-criticized response on the alleged Chinese encroachment on Benham Rise and reports that Beijing is also planning to build a radar station in Scarborough Shoal.

China has since denied it will build an environmental monitoring station on Scarborough Shoal.