If 47 percent of American voters weren't in the bag for President Barack Obama before, they certainly are now. The video of Republican presidential nominee Mitt Romney writing off nearly half of the American population as layabouts with no feeling of personal responsibility, a victimhood complex and an addiction to government services may hit a new high-water mark for self-inflicted wounds in an electoral campaign, not just because it was insulting but because it points squarely at a question Mr. Romney has failed to sufficiently answer: Will his policies benefit the many or just the few?

Mr. Romney's remarks at a fundraiser this summer, which were posted online by Mother Jones magazine, bring about ready comparisons to comments then-presidential candidate Barack Obama delivered at a San Francisco fundraiser in 2008. In another surreptitiously recorded video, Mr. Obama is caught describing small-town Pennsylvania voters as "bitter" and clinging "to guns or religion or antipathy to people who aren't like them." That remark also connected with a lingering question about his candidacy — whether he was a snobbish, intellectual elitist who disdained small-town American culture and values.

Mr. Obama recovered, and Mr. Romney certainly can, too, but he needs to muster a better response than he has so far. Mr. Obama's comments were at least couched in concern about the economic straits many Americans found themselves in after the Clinton and Bush administrations. Mr. Romney's were flatly dismissive: "My job is not to worry about those people. I'll never convince them to take personal responsibility and care for their lives." He didn't even have much flattering to say about the 5 percent to 10 percent of voters he said were persuadable, the independents "that are thoughtful, that look at voting one way or another depending in some cases on emotion, whether they like the guy or not." And rather than backing down, claiming to have been taken out of context or even apologizing, Mr. Romney stood by the substance of what he said.

The entire exchange suggested that Mr. Romney has spent too much time listening to Fox News — where the percentage of Americans who don't pay income tax is a recurring theme — and not enough time listening to voters who find themselves in the uncomfortable position of applying for food stamps and unemployment benefits for the first time in their lives. Missing from the speech was any acknowledgment that the rise in Americans receiving aid of one kind or another in recent years is due to anything more than individuals' personal failings. It sounded as if Mr. Romney believed the recession was caused by a collective decision by half of the nation to stop trying. Moreover, it gave the wrong impression about who, exactly, is benefiting from government programs. To get anywhere close to the 47 percent figure Mr. Romney cited, you'd have to throw in Medicare and Social Security recipients, people who have subsidized student loans and others who don't come close to the stereotype he portrayed.

Strictly speaking, Mr. Romney was talking about politics, not policy. When he said he wasn't going to worry about those people, he meant he wasn't going to busy himself with trying to get them to vote for him, not that he wasn't going to try to improve their prospects if elected. The problem is, he has done precious little to explain how his policies would benefit the middle class and the poor. He promises to bring millions of new jobs to America, but he has done little to explain how another round of cutting taxes and eliminating regulations would be more effective than it was during the George W. Bush administration.

He has promised across-the-board income tax rate reductions, but as he astutely notes in his remarks, that has little salience for the millions of Americans who earn too little to pay income taxes in the first place. And given his simultaneous pledges to reduce the deficit and increase defense spending, voters have reason to be worried about the details he has not provided about the spending cuts and elimination of deductions that would be required to make the math work, if indeed it can.

Recent polls indicate that Mr. Obama has caught up to Mr. Romney on the questions of who would better handle the economy and tax policy, and part of the reason must surely be the suspicion, stoked relentlessly by the Obama campaign, that the Republican's policies would do too much to help the rich and too little to help everyone else. If Mr. Romney has an answer to that, he needs to provide it. News reports before this video surfaced suggested that the Republican's campaign planned to provide more details in the coming days about his economic policies. Now that is an imperative.

Mr. Romney has been a gaffe-prone candidate from the start, and pundits are typically quick to declare each new flub a game-changer that will decide the election. That's a little over-dramatic. The American people are smart enough to make decisions based on more than a gotcha video posted on the Internet. Mr. Romney's problem is not what he said in that fundraiser. It's that he has acted for so long like all he needed to do to win this election was to not be Barack Obama. That has left a vacuum at the center of his campaign that is too readily filled by stories like this one. The only cure for that is for Mr. Romney to offer more substance, specifics and honesty about the tough choices ahead. There's not much time left. For his sake, and for the sake of American voters looking to make an informed decision in November, he'd better get started.