Wednesday’s presidential debate may or may not have changed the race for John McCain, but there was one thing that did remain constant: the amorphousness of the middle class.

McCain “keeps referring to Joe, who in these first few minutes of the debate has become the universal middle-class taxpayer,” wrote Katherine Seelye on The New York Times’s Caucus live blog Wednesday night, as the Republican candidate brought Joe Wurzelbacher, an aspiring plumbing entrepreneur who stood to draw a $250,000 salary in the near future, to the debate table. The Boston Globe called Joe “an election-year everyman for a nation on the cusp of a potentially deep recession.”

A $250,000-per-year everyman? The real median household income in 2007, according to the latest Census Bureau survey, was $50,233. Joe may be the living, breathing figure of the hard-earned American Dream, but if his business scenario has him topping $250,000, he would not exactly be the average American taxpayer. Since Wednesday night, it’s been revealed that Joe the Plumber is not the soon-to-be rich man that McCain depicted him as. But that wasn’t common knowledge when yesterday’s papers were printed. And the en-masse portrayal of Joe Wurzelbacher as an average Joe of the middle class also emphasizes how broad the political definition of “middle class” has become—and how lax the media have become in challenging that definition.

Both Obama and McCain have made good mileage trying to plump their plans for America’s middle class, that broad expanse often equated to the middle three quintiles of the Census Bureau’s five-part income distribution methodology.

But as the debate again showed, the definition of middle class (and by proxy, the definition of upper class), is abundantly and repeatedly swayed for political gain—and for good reason. A Pew Research Center survey from earlier this year found that about half (53 percent) of all Americans think of themselves as middle class, even when those who self-identified as middle class had a wide range of incomes:

But within this self-defined middle class, there are notable economic and demographic differences. For example, four-in-ten Americans with incomes below $20,000 say they are middle class, as do a third of those with incomes above $150,000. And about the same percentages of blacks (50%), Hispanics (54%) and whites (53%) self-identify as middle class, even though members of minority groups who say they are middle class have far less income and wealth than do whites who say they are middle class.

And it is this wide-ranging self-alignment—and not strict definitions—that both politicians more often cater to in their stump speeches. And that’s unsurprising; appealing to voters through the amorphous vehicle of class is a tried and true (and often a well-intentioned) political tactic. But because political speech is so often driven by code phrases like this, the press should be even more active in combating imprecision of language, rather than allowing politicians and their cohorts to sap such terms of their most functional meaning.

So if anything, this means that labels like “middle class” deserves re-examination, not inflation—and if not from the candidates, then from the press. They shouldn’t be so easily repackaged. For instance, when Sara Taylor, former Bush White House political affairs director, is quoted as describing Sarah Palin in a Los Angeles Times article as a “living, breathing replica of the middle class,” we should take a step back and say, wait, how are assets topping $1 million aligned with the middle class? Or, we might question the exactitude of this conclusion about the debate from the NYT: “[McCain] managed to change the subject from the economy, as he tried to woo independent and working-class voters and put himself on the side of the working man. And in this bad economy, he even knows his name: Joe.” The inflation of labels beyond the limits of their definitions—and used instead to make broad politician woos x voter-group statements—makes it that much easier to ignore, conflate, or distort the specific and real issues confronting the real working and middle classes. And that’s a problem.

Similarly, during last night’s debate, McCain’s sarcastic use of the word “rich” in reference to Joe W. should remind us that the middle class receives a generous political definition for a reason: it allows the candidates to shape their policies most flexibly, and regardless of party, to maintain as much of a populist tinge as benefits them. It’s also the more convenient way to address the “what is rich?” question that has floated around the campaign since Saddleback. But waving a “not rich” wand is no way to categorically define such a large swathe of our population.

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Jane Kim is a writer in New York.