Giuliani, the former New York City mayor and 2008 Republican presidential candidate, told cheering Whitman supporters in a Los Angeles hotel that electing Democrat Jerry Brown would be a step backward in a state with a double-digit unemployment and a financial crisis in state government. He depicted Brown as a vestige of failed Democratic policies who hadn't earned a return trip.
"You want to go back to those eight years?" Giuliani asked the invited audience, referring to Brown's years as governor from 1975 to 1983. He praised Whitman's business credentials -- she's a former chief executive at eBay -- and called her "the right person at the right time for the kinds of challenges that California faces."
The value of endorsements is often questioned, but Whitman is hoping that Giuliani's celebrity and his record in New York -- he is known for his leadership after the World Trade Center attacks and helping steer the city out of the recession of the early 1990s -- will resonate with California voters.
"Rudy Giuliani is very popular in California, because he turned around New York City. And the question I get every day on the campaign trail is, 'Can California be fixed?"' Whitman said.
Questioned by a reporter about a recorded voicemail message in which an unidentified Brown aide refers to her as a "whore" because of her attempt to curry favor with a law enforcement union, Whitman said she considers the word a slur but didn't call for Brown to personally apologize.
Later, she said she wanted the campaign to concentrate on issues voters care about. "They want to know what I am going to do about jobs," she said.
Giuliani took a beating in the 2008 presidential race, but he was an early leader in the California primary. He remains is a fixture on the Republican campaign circuit, and he is making stops this week on behalf of candidates in several Western states.
Recent polls show Whitman and Brown in a tight race. The outcome of statewide races are often determined by independents, and Whitman is at a disadvantage because Republicans account for only about one in three voters in California.
While Whitman was happy to have Giuliani at her side, she won't be joining another GOP luminary this week: Sarah Palin. Whitman will not attend a high-profile GOP fundraiser in Orange County this week where Palin is the headliner -- her campaign says she has other commitments that day.
A recent Field Poll found Palin is not a popular figure in California -- about two of three independents said they would be less likely to support a candidate endorsed by the former Alaska governor.
California is like much of America: Voters are in a funk.
California's next governor will inherit a multibillion-dollar budget hole, but neither candidate has offered a detailed solutions to those issues frightening voters: 12.4 percent unemployment, sinking home values and an erosion of state services witnessed from classrooms to state parks.
Whitman, who routinely criticizes Brown for his ties to Sacramento labor unions, warned that putting him in charge would mean more of the same: spending and deficits.
Giuliani endorsed Whitman last year. But he wasn't Whitman's favorite in the presidential race: She was an economic adviser to candidate Mitt Romney and, later, a co-chair for GOP nominee John McCain's campaign.
The former mayor is mentioned as a possible presidential candidate in 2012, and he took several pointed jabs at President Barack Obama: "We've certainly lost our way in Washington, D.C.," he said. Giuliani glossed over his record in New York -- he said he "cut spending" but didn't mention that spending increased during most of the years he was in office.