Romney neither disavowed nor apologized for his remarks, which included an observation that nearly half of the country believe they are victims and entitled to a range of government support. Instead, Romney cast his comment as evidence of a fundamental difference with Obama over the economy, adding the federal government should not "take from some to give to the others."

As the rivals sparred with seven weeks remaining in a close race for the White House, two GOP Senate candidates publicly disavowed Romney's remarks and Republican officials openly debated the impact that a series of controversies would have on the party's prospects of winning the presidency.

Top Republicans in Congress declined through aides to offer their reaction to Romney's remarks - just as they generally refrained from commenting a week ago when he issued a statement that inaccurately accused the Obama administration of giving comfort to demonstrators after they breached the U.S. Embassy in Cairo.

The most recent controversy in a campaign filled with them was ignited by the emergence of a videotape, made last May, in which Romney told donors at a fundraiser that 47 percent of Americans pay no income taxes. They "believe the government has a responsibility to care for them ... believe that they are entitled to health care, to food, to housing, to you name it. That that's an entitlement."

He said, "I'll never convince them they should take personal responsibility and care for their lives."

In a next-day interview on Fox, the network of choice for conservatives, Romney said he didn't intend to write off any part of a deeply divided electorate, including seniors who are among those who often pay no taxes. Instead, he repeatedly sought to reframe his remarks as a philosophical difference of opinion between himself and Obama.

"I'm not going to get" votes from Americans who believe government's job is to redistribute wealth," he said, adding that was something Obama believes in.

He also said he wants to be president so he can help hard-pressed Americans find work and earn enough so they become income taxpayers.

Romney didn't say so, but the U.S. income tax is designed to be progressive, so those who earn the most theoretically pay the most. Through programs as diverse as Social Security, Medicare, health care and food stamps, the government collects tax revenue and pays it out in the form of benefits for those who qualify.

Obama responded during an appearance on the David Letterman show.

"One thing I've learned as president is that you represent the entire country," he said. As for Romney's statement about the 47 percent, he said, "There are not a lot of people out there who think they are victims" or simply entitled.

At the same time, his campaign released a new ad saying that if Romney wins the White House, he might seek the elimination of a series of tax breaks used by millions of middle class Americans. "Mitt Romney, he's so focused on big business and tax cuts for the wealthy, it seems like his answers to middle class America are just tough luck," says a woman in the commercial.

For his part, Romney referred to videotaped comments Obama made in 1998 as evidence he favored government redistribution of wealth. As an Illinois state senator at the time, Obama said he believes in it "at least to a certain level to make sure everybody's got a shot."

Privately, some Republicans were harshly critical of Romney's most recent comments and his overall campaign to date, saying he had frittered away opportunities. They also noted that with early voting already under way in some states, the time to recover was smaller than might appear.

Linda McMahon, the Republican candidate for a Senate seat in Connecticut, was open with her criticism. "I disagree with Governor Romney's insinuation that 47% of Americans believe they are victims who must depend on the government for their care," she said in a statement posted to her website.

Sen. Scott Brown, in a tough race for re-election in heavily Democratic Massachusetts, said of Romney's comments: "That's not the way I view the world."

Still, with high-profile presidential debates and seven weeks of campaigning yet ahead, others said those concerns were overstated.

"I don't expect the negative headlines of this week will be what we're talking about a week from now," said Fergus Cullen, the former Republican state chairman in New Hampshire and a close ally of Romney. Like other Republicans, he said, "It's incumbent on the Romney campaign to make it [the election] about Obama's handling of the economy."

In recent days, Republicans have grumbled that Romney needed to sharpen his appeal to struggling middle class Americans by stating more clearly what he would do as president to help them. That effort began overnight with a new ad designed to appeal to female voters.

The new controversy blazed as opinion polls suggested that a narrow lead Obama gained nationally and in some key battleground states in the wake of the Democratic National Convention might be ebbing.

The sluggish economy and lingering high unemployment are by far the overriding issues of the election, and Romney's case for the presidency is based on his claim that his success as a businessman has left him the skills needed to create jobs in a nation where unemployment is 8.1 percent.

Obama and the Democrats have tried to counter by depicting the president's challenger as a multimillionaire who has some of his wealth invested in the Cayman Islands and elsewhere overseas, and is out of touch with the needs of middle class Americans.

In his original reaction to the video, posted by the left-leaning magazine Mother Jones, Romney told reporters Monday night that his fundraising remarks were "not elegantly stated." But he offered no apologies and did not answer directly when asked if he felt he had offended anyone.