The ICC decision enables prosecutors to present their case that Duterte was "at the very heart" of brutal anti-drug campaigns launched during his time as mayor of Davao City and later as president, according to charges detailed by the court.

"The available evidentiary material shows the existence of a common plan between Mr Duterte and his co-perpetrators to kill alleged criminals in the Philippines, including those perceived or alleged to be associated with drug use, sale or production, through violent crimes including murder," the ICC stated in its Thursday ruling.

The court's jurisdiction extends to alleged crimes committed between 2011 and 2019, while the Philippines remained an ICC member state. This timeline covers Duterte's final years as Davao mayor and his early presidency, when the most intensive phases of the drug war occurred.

Duterte's legal team maintains his innocence. "Former President Duterte maintains his innocence absolutely," his lawyer stated following Thursday's announcement, according to Fox News. The defense has consistently argued that the drug operations constituted legitimate law enforcement rather than systematic murder.

For critics of Duterte's presidency, the ICC confirmation represents vindication after years of advocacy. Leila de Lima, a member of the Philippines' House of Representatives and one of Duterte's staunchest critics, called the confirmation of his crimes against humanity charges "a great day for the fighters against impunity and state-sponsored violence."

The Thursday confirmation follows years of legal maneuvering. Duterte withdrew the Philippines from the ICC in March 2019, one month after the court announced it would investigate his drug war policies. Human rights activists characterized the withdrawal as an attempt to avoid accountability.

However, on Wednesday, judges in the ICC's Pre-Trial Chamber ruled that the court could still hear Duterte's case, given that the alleged crimes had happened between 2011 and 2019 while the Philippines was still an ICC member. This jurisdictional window covers the period when Duterte's anti-drug operations were most intensive and deadly.

Maria Elena Vignoli, senior international justice counsel at Human Rights Watch, said the trial sends a signal to other leaders facing similar allegations worldwide. The prosecution will "send a powerful message that no one responsible for grave crimes is above the law, whether in the Philippines or elsewhere, and that justice will eventually catch up with them," she said.

The case now advances to trial proceedings, where prosecutors must prove beyond reasonable doubt that Duterte personally directed or knew about specific killings carried out under the guise of anti-drug operations. The prosecution faces the challenge of demonstrating systematic planning rather than isolated incidents of police misconduct.

Duterte's supporters have long argued that his drug war reflected popular demand for aggressive action against narcotics-related violence plaguing Philippine communities. Public opinion polls during his presidency showed initial support for the operations, though approval declined as death tolls mounted and extrajudicial killing reports increased.

The ICC proceedings will test whether international courts can prosecute leaders whose governments claim anti-drug enforcement, establishing a legal framework that could reshape how the Philippines and other nations face scrutiny over police-conducted killings.