SAN FRANCISCO >> Libby Schaaf, the Democratic mayor of Oakland since 2015, stepped into the middle of the national debate on immigration on Saturday when she warned of imminent raids by federal immigration agents in the San Francisco Bay Area.

The next day the raids began, and the deputy director of Immigrations and Customs Enforcement said Schaaf’s warning had compromised the safety of agents and allowed targets of the raid to flee.

In a city that for decades had one of California’s highest rates of violent crime, the number of burglaries, murders and shootings have sharply declined during Schaaf’s three years as mayor. Yet her tenure has made national headlines for scandal, tragedy and the disappointment of an iconic sports team announcing its plans to move.

Here’s a look at Schaaf’s background and time as mayor.

CHILD OF OAKLAND, ADVOCATE FOR DIVERSITY

Schaaf, 52, is a dyed-in-the-wool liberal in a city where “Republican” is a dirty word.

“Oakland has always been a place for social justice movements,” Schaaf said in an interview. “We’re a city that is fiercely proud of our diversity, full of artists and unique creative energy, but with a gritty authenticity.”

Born in Oakland to a former flight attendant and traveling shoe salesman, Schaaf grew up in the Oakland Hills, a residential area more affluent and geographically distinct from the downtown parts of Oakland that suffered the crack epidemic and a flight of major businesses to other parts of the Bay Area. Schaaf — whose mother was deeply involved in civic projects, including running a volunteer program at a children’s hospital — has lived in the city most of her life, though she went to college in Florida and law school in Los Angeles.

Schaaf worked as a lawyer for two years at a prominent law firm in Oakland before turning to politics. She served several years as an aide to other politicians, including Gov. Jerry Brown when he was mayor of Oakland, and was elected to the City Council in 2010. Four years later she was elected mayor.

As a former lawyer, Schaaf understands the potential pitfalls in warning unauthorized immigrants of an impending raid. But she approaches the issue in the style of an activist.

Asked what her message was for immigrants who are in Oakland illegally, Schaaf said: “Your city wants you to be safe, wants to keep your family together and is proud to have you as part of our community.”

HOUSING AFFORDABILITY HAS BEEN A CONCERN

The past few years have been a time of wrenching change for Oakland. The wealth generated by the tech industry across the San Francisco Bay is pushing up housing prices and making many neighborhoods unaffordable to any family not earning six figures. The economic pressures have caused the number of homeless to rise to around 2,800, an increase of more than 25 percent since Schaaf took office in January 2015.

In the city that gave rise to the Black Panthers, the African-American community has been shrinking dramatically, from 47 percent of the population in the 1980 census to less than one-quarter today. As black residents have moved out, Latinos and Asian-Americans have moved in.

Schaaf has had to balance the courting of technology companies with the changes to the traditional working-class character of the city. “Hey, Google: You wouldn’t need all those buses if you’d open an office over here,” she was quoted as saying on the day of her swearing in.

In December 2016, when 36 young people died in a fire at a warehouse that had been converted into an illegal artist colony and party venue, the subtext was that the shortage of affordable housing had pushed artists into dangerous living conditions. In the aftermath of the Ghost Ship fire, as it is known, Schaaf juggled the competing demands for greater safety with concerns from artists that they might be forced to leave the city if fire codes were strictly enforced. She was criticized for not disciplining or removing the city’s fire chief, who in the years before the Ghost Ship fire had been accused of keeping the department understaffed and disorganized.

A POLICE SCANDAL ON HER WATCH

The Ghost Ship fire was the worst structural fire in America in more than a decade. The NFL’s Raiders announced they were leaving Oakland for Las Vegas. And a 2016 scandal in the police force — a prostitute said she had sex with a number of police officers, and at least one of them had tipped her off to police raids — threatened to derail one of Schaaf’s main campaign promises: reducing crime. Schaaf stumbled. The city had three police chiefs within the span of a week.

“I am here to run a Police Department, not a frat house,” Schaaf said in what became a cable-news sound bite du jour.

Last year, Schaaf announced the appointment of a new police chief.

The faceoff with ICE is likely to score her political points in such an unabashedly liberal city, and Schaaf says she will continue to advocate for those being displaced by rising housing prices and for undocumented residents threatened with deportation.

“I grew up with an acute awareness of the disparities within my own community,” she said. “It’s certainly something you can’t escape in Oakland.”

She is running for re-election in November.