Move over, Willie Horton. The latest villain in political attack ads, at least in one Senate race in California, is Leona Helmsley.

State Controller Gray Davis, who is badly trailing former San Francisco mayor Dianne Feinstein in polls before Tuesday's Democratic primary, began airing a television ad this week that compares Feinstein to the convicted New York hotel queen. Helmsley is serving a four-year prison term for tax evasion, mail fraud and conspiracy. Feinstein was recently sued by a state panel over alleged campaign-finance violations.

Kam Kuwata, Feinstein's campaign manager, yesterday called the ad "cheap and sleazy."

"It's a desperation move by a very desperate candidate," Kuwata said. "The ad is very offensive to Jewish-Americans and women. Who does he pick out for this McCarthyite guilt-by-association? A Jewish woman."

Davis, in an interview, called the criticism "preposterous." He said the ad was written by a Jewish consultant, Michael Berman, and that its purpose "is to show two individuals, both of whom refuse to admit culpability for their respective wrongdoing.

"We've come to a sorry state in this country if you can't criticize a woman without being accused of sexism. It does a disservice for people to use their ethnicity as an excuse for what they did."

The commercial opens with side-by-side pictures of Helmsley and Feinstein.

"Helmsley blames her servants for the felony," the narrator says. "Feinstein blames her staff for the lawsuit. Helmsley is in jail. Feinstein wants to be a senator." On the screen, a picture of Helmsley, depicted as behind bars, gives way to some Roman columns crumbling around Feinstein.

The tag line is "truth for a change." But the Gray ad stretches the truth by linking Helmsley's criminal activities with a civil suit accusing Feinstein of campaign-finance violations.

The state's Fair Political Practices Commission sued Feinstein last month, saying she improperly reported more than $8 million in donations and expenditures during her 1990 race for governor. The violations, described by the panel's chairman as "gross negligence," include a failure to disclose that Feinstein's husband had cosigned $2.9 million in loans to her campaign.

Kuwata, blaming the violations on sloppy bookkeeping, said there were "political motivations" to the suit because the commission is now headed by a Republican named by Gov. Pete Wilson (R) for the seat he vacated when he defeated Feinstein in 1990. If Feinstein wins Tuesday, she is likely to face interim appointee, Sen. John Seymour (R), in November. He is favored to win the GOP primary.