"The negative environment around the drug war and a lack of positive results in other areas are driving public frustration with the government," explained Eufracia Taylor, Asia analyst at consultancy Verisk Maplecroft. "What about employment, infrastructure, and corruption? Those things have been neglected under the framework of the drug war and we're seeing the cost of that now."
Until now, most Filipinos widely supported Duterte and his aggressive narcotics crackdown in the belief that his policies were making the country safer. Recent police figures say 3,850 have died during drug enforcement operations between July 2016 and September this year.
But human rights groups, which say the death toll is much higher, have long condemned the outspoken head-of state for sanctioning lawlessness and extrajudicial killings in his crime-fighting pursuit. Public opinion seems to be catching up following an Aug. 16 killing of a teenager that drew attention to widespread allegations of police brutality and triggered fresh protests against Duterte's administration.
Complaining about what they called rising tyranny, thousands of Filipinos rallied on Sept. 21. Doubt over presidential actions, including the imposition of martial law in the city of Marawi and the silencing of critics, underlined the movement.
"Because the president's signature programs are related to law and order, failings and missteps in these domains can reflect on his leadership," said Victor Manhit, managing director at business advisory firm Bower Group Asia.
In a Monday statement, presidential spokesman Ernesto Abella said the ratings drop was "expected, given the fact that people start measuring their expectations usually after the honeymoon period or after a year in office." The president's trust rating remains "very good," he added.