Mayors, particularly in big cities, must be highly effective managers. And even marginally effective managers must know better than to sexually harass underlings.

But that practical reality didn’t stop San Diego Mayor Bob Filner’s attorney from demanding Tuesday that the city pay for his client’s defense against sexual-harassment charges.

The basis for that galling claim: The city supposedly didn’t provide sexual-harassment training for Mr. Filner.

However, Mr. Filner, a Democrat who served 10 terms in the U.S. House before winning the San Diego mayor’s race last year, maintains his innocence of sexual-harassment allegations that eight women have made against him.

So if Mr. Filner didn’t make crude advances to those women, why should the city be liable for a perceived lack of training on how to avoid sexual harassment he didn’t commit?

Mayor Filner, who turns 71 next month, has rejected rising calls for his resignation.

Yet though he officially denies the harassment allegations, he has admitted that “I have failed to fully respect the women who work for me and with me, and that at times I have intimidated them.” The mayor also said, “I need help” — and that he will begin “two weeks of intensive therapy” during a leave of absence starting Monday.

Thus, Mr. Filner has cast himself as a victim, too.

Meanwhile, the mayor’s mess casts more light on a troubling trend: Many modern politicians refuse to go away despite thorough public disgrace.

Ponder the Sept. 10 Democratic Primary ballot in New York City: Anthony Weiner is running for mayor despite being forced to resign from Congress in 2011 due to a scandal, recently re-booted, about his appalling habit of “sexting” explicit material, including revealing images of himself. Eliot Spitzer is running for comptroller despite being forced to resign as governor in 2008 after being implicated as a prostitution patron.

Some politicians apparently do need “intensive therapy” to control their addictions — not to sex, but to power.

As for Mr. Filner, eight — as in eight women allegedly harassed and eight months as San Diego’s mayor — is enough.