My first reaction to Bill Clinton's convention speech was sheer professional jealousy: nobody, but nobody, has his ability to translate economic wonkery into plain, forceful English. In effect, Mr. Clinton provided an executive summary of the new Census report on income, poverty and health insurance - but he did it so eloquently, so seamlessly, that there was no sense that he was giving his audience a lecture.

    My second reaction was that in Mr. Clinton's speech - as in the speeches by Hillary Clinton and Joe Biden (this column was filed before Barack Obama spoke on Thursday night) - one heard the fundamental difference between the two parties. Democrats say and, as far as I can tell, really believe that working Americans are getting a raw deal; Republicans, despite occasional attempts to sound sympathetic, basically believe that people have nothing to complain about.

    As it happens, the numbers support the Democrats.

    That Census report gives a snapshot of the economic status of American families in 2007 - that is, before the financial crisis started dragging the economy down and the unemployment rate up. It's a given that 2008 will look much worse, so last year was as good as it will get in the Bush years. Yet working-age Americans had significantly lower median income in 2007 than they did in 2000. (The elderly, whose income is supported by Social Security - the program the Bush administration tried to kill - saw modest gains.) Meanwhile, poverty was up, and health insurance - especially the employment-based insurance on which most middle-class Americans depend - was down.

    But Republicans, very much including John McCain and his advisers, don't believe there's a problem.

    Former Senator Phil Gramm made headlines, and stepped down as co-chairman of the McCain campaign, after he described America as a "nation of whiners." But how different was that remark, really, from Mr. McCain's own declaration that "there's been great progress economically" - progress that's mysteriously invisible in the actual data - during the Bush years? And Mr. Gramm, by all accounts, remains a key economic adviser to Mr. McCain.

    Last week John Goodman, an influential figure in Republican health care circles, explained that we shouldn't worry about the growing number of Americans without health insurance, because there's no such thing as being uninsured. After all, you can always get treatment at an emergency room. And Mr. Goodman - he's the president of the National Center for Policy Analysis, an important conservative think tank, and is often described as the "father of health savings accounts," a central feature of the Bush administration's health policy - wants the next president to issue an executive order prohibiting the Census Bureau from classifying anyone as uninsured. "Voilà!" he says. "Problem solved."

    The truth, of course, is that visiting the emergency room in a medical crisis is no substitute for regular care. Furthermore, while a hospital will treat you whether or not you can pay, it will also bill you - and the bill won't be waived unless you're destitute. As a result, uninsured working Americans avoid visiting emergency rooms if at all possible, because they're terrified by the potential cost: medical expenses are one of the prime causes of personal bankruptcy.

    Mr. Goodman has in the past, including in an op-ed for The Wall Street Journal, described himself as an adviser to the McCain campaign on health policy. The campaign now claims that he is not, in fact, an adviser. But it's a good bet that Mr. McCain's inner circle shares Mr. Goodman's views.

    You see, Mr. Goodman's assertion that lack of health insurance is no problem precisely echoed what President Bush said a year ago: "I mean, people have access to health care in America. After all, you just go to an emergency room." That's because both men - like Mr. Gramm - were just saying in public what modern Republicans say when they talk to each other. Despite attempts to feign sympathy, the leaders of today's G.O.P. fundamentally feel that Americans complaining about their economic and health care difficulties are, well, just a bunch of whiners.

    And that, ultimately, even more than their policy proposals, is what defines the difference between the parties.

    It's true that elected Democrats are often too cautious - and too beholden to major donors - to be as progressive as the party's activists would like. But even in the face of a Republican Congress, Mr. Clinton succeeded in pushing forward policies, like the State Children's Health Insurance Program, that did a lot to help working families.

    And what one sees on the other side is a total lack of empathy for and understanding of the problems working Americans face. Mr. Clinton, famously, felt our pain. Republicans, manifestly, don't. And it's hard to fix a problem if you don't even think it exists.