But he also quickly went on the offensive, seizing on the issue of illegal immigration to jab his chief rival, Rudolph W. Giuliani, by accusing the former New York mayor of turning the city into a magnet for illegal immigrants and comparing his record on the issue to that of Democratic front-runner Sen. Hillary Rodham Clinton.
Giuliani "was responsible for a sanctuary city. . . . He welcomed the illegal aliens to the city," Romney told reporters after his "town hall meeting." "That sanctuary state of mind is one of the reasons we have so many illegal immigrants in our country today."
The sniping between the two GOP candidates has intensified as the former Massachusetts governor nurses a narrow lead in the upcoming Iowa caucuses and New Hampshire primary. Victories in those contests, the first en route to the GOP nomination, are essential to Romney's effort to gather the political momentum to surmount Giuliani's lead among Republican voters in national polls.
The mostly Republican crowd at the "Ask Mitt Anything" gathering, held at the Burbank Airport Marriott Hotel and Convention Center on the edge of the Bob Hope Airport, provided evidence about why Romney has aggressively used illegal immigration as a political spear against Giuliani. Romney's promise to crack down on illegal immigrants received the loudest applause at the event.
The crowd included a mixture of Romney campaign supporters and local business leaders, including members of the Valley Industry and Commerce Assn., as well as a handful of disinterested high school students assigned to write term papers on the event. It was Romney's fourth "Ask Mitt Anything" meeting in California.
Romney arrived in Southern California on Wednesday and went to work mining the GOP-friendly Inland Empire for campaign funds and support during a trio of private fundraisers in Upland, Riverside and Redlands.
On Thursday night, the campaign headed to Las Vegas, where the Democratic presidential candidates were squaring off in a debate.
"The only place that you can lose more money than in the casinos in Las Vegas will be in that debate," he told the Burbank crowd, drawing a big laugh. "They're after your wallets."
During the meeting, Romney outlined his plan to provide tax relief for the middle class, saying it was a key ingredient in preserving American families.
He said he would eliminate taxes on interest, dividends and capital gains for families earning less than $200,000 a year. To make up for lost revenue, he said, he would hold non-defense spending to 1% below the inflation rate.
He said economic growth triggered by the tax cuts would also help pay for tax relief.
Given the continuing dire news about the housing market, Romney also tailored his message to struggling homeowners by saying that the tax breaks would help those on the financial edge to make their monthly mortgage payments.
Romney also welcomed audience questions about the Massachusetts healthcare plan, which was designed to reduce the estimated 500,000 uninsured residents in that state.
Under the program, all residents were required to be insured through government programs or private insurance provided by their employers, subsidized by the state or purchased on their own.
His GOP rivals on Thursday attacked the plan as the antithesis of fiscal conservatism.
"We can get everybody insured in this country without socialized medicine, without a government-run system and without new taxes required," Romney said, adding that as president he would want states to adopt their own programs.
Romney dismissed criticism from GOP presidential hopeful Fred Thompson and others, who said the mandates ran counter to conservative ideals.
"At least I have a program," Romney said.