Congressman Romeo Jalosjos, for example, received a double life sentence for raping an 11-year-old girl. Yet from behind bars he won re-election twice. And the president commuted his sentence in 2009 — after only 13 years in jail.

Similarly, President Joseph Estrada, in office from 1998 to 2001, celebrated having many mistresses. His 2007 life imprisonment for corruption resulted partly from investigations into the mansions he provided them. He was quickly pardoned by his successor, to assuage pressure by his supporters and relatives in government. Mr. Estrada is now mayor of Manila.

Our new president, Rodrigo Duterte, seems to understand well how machismo and chauvinism can be spun as populist proof of shared veniality. This septuagenarian boasts of having two wives and two girlfriends, and his love of Viagra. He harassed a female reporter during a news conference. He infamously bantered about raping an Australian missionary.

All that is dismissed by Mr. Duterte’s supporters as proof of his authenticity, innocuous wit or frankness about the West and its values. Some prominent women’s groups even back him because of his laudable initiatives when he was a mayor. He established laws against harassment and discrimination, distributed contraceptives and is said to have spent his own money on lawyers for battered women.

Yet, he, too, has no problem playing on gender biases for political ends.

Recently, an opposition senator, Leila de Lima, led an investigation into the thousands of murders committed during Mr. Duterte’s drug war. The president described Ms. de Lima as “immoral” and an “adulterer.” He said that he had seen a video of the senator having sex with her driver, who, he alleged, was her link to drug lords.

That declaration titillated the nation. Like insecure schoolboys in the locker room, Mr. Duterte’s allies gleefully followed his lead. One congressman seconded the president’s remark that the video made him lose his appetite, adding that it was a “horror story” featuring “ugly performers.” Another congressman said: “The male performer is good.”

No charges have been filed against Ms. de Lima, and the video was debunked as showing a look-alike. Yet the tactic was the dirtiest of many that succeeded in discrediting her opposition to the president.