Impeachment rap vs Duterte bound to fail - legal experts

Metro Manila (CNN Philippines) — Bound to fail.

Even House Deputy Minority Leader Harry Roque agrees with pro-administration legislators that the impeachment case against President Rodrigo Duterte will simply go down the drain.

Roque, himself and international and constitutional law expert, explained on Friday that Duterte could not be held liable, or impeached, for acts which had happened before he became president.

Related: Impeachment complaint vs. President won't prosper

Self-confessed hitmen Edgar Matobato and Arthur Lascañas previously faced the Senate and said that Duterte had ordered them to kill — when he was still the mayor of Davao City.

Dean Nilo Divina of the UST College of Law agrees — saying that charges should have been brought before Duterte took office as president — or after his term expires in 2022.

"One can only be impeached for acts during his incumbency, not for acts before his assumption to office," Divina said.

Another point raised by Roque was that the President's link to extrajudicial killings or EJKs in connection with the war on drugs was "non-existent at worst and tenuous best."

"We are confronted with a figure of 8,000 deaths from Tokhang; yet, how many of these have been properly documented so as to establish clear lines of culpability leading to the President?" Roque said in a statement.

The lawmaker said there was lack of case building in crafting the impeachment rap and noted that only one impeachment case may be filed against the president per year.

"In their hasty desire to bring down the President, they may have squandered this opportunity to do so," Roque said. "Haste makes waste."

CNN Philippines' Joyce Ilas contributed to this report.