Last week exposed some of the fault lines in Republican party ideology, as Mitt Romney’s characteristics as an economic actor received closer scrutiny, paradoxically threatening the integrity of the rhetoric on which Republicanism relies.

In itself, Mr Romney’s wealth need not be embarrassing.  Americans have always had a soft spot for wealthy presidents (think of the Roosevelts and the Kennedys), and many wealthy Americans have made fine public servants (think John Kerry, Nelson Rockefeller, George Bush senior, or Michael Bloomberg).  No, the embarrassment springs from the contrast between Mr Romney’s profile and the way, in Republican discourse, rich people are typically styled.

All last year, many of us watched in wonder as the party’s congressional leadership repeatedly balked at the idea of increasing the tax obligations of the wealthiest Americans, specifically those earning $1 million a year or more.  In a year dominated by the debt-ceiling controversy, quarrels over the Bush tax cuts, and abortive attempts to arrive at a balanced-budget plan, leading Republicans stalwartly defended the interests of the super-rich, even at the expense of significant political gains.

Republicans justify their resistance to increasing taxes on the nation’s top earners by consistently portraying them as struggling small-business owners and entrepreneurs, whose uppermost thought is how to use their every spare dollar to employ more Americans and create jobs.

Republicans persist in this despite the fact that, as others have pointed out, the description is misleading.  The characteristics of the nation’s top earners are far more varied.  Many are principals in businesses that are incorporated, their compensation a disembodied gift that they and their families are free to use as they please.  Others derive the bulk of their income from masses of investments or speculation, i.e., from unearned income like capital gains.

Each time I heard the Republican leadership describing this class of people as struggling job-creators, I wondered, “Do voters buy this?  And how many ordinary people actually want to give a break to people so much more wealthier than they?”  Since polls have repeatedly shown that most Americans favor taxing the wealthiest more heavily, the Republicans seemed to be playing a dangerous game.  Yet all through 2011, they stayed on message, and they got their way, beating back every measure to tax high-earning individuals more fairly.

Now, as if on cue, enter Mitt Romney, a living exemplar of the class the Republicans have been defending.  Mr Romney has suddenly brought certain issues into focus in a way that even the Republicans’ fiercest opponents could not have managed.  For Mr. Romney’s exceptional wealth and privilege, along with the nature of Bain Capital‘s activities, bring into question the entire Republican worldview, even as Romney entreats rank-and-file Republicans to support his candidacy and make him the standard-bearer in their common cause.

It’s not just that Mr Romney’s fortune, pegged conservatively at some $190 million, derives from hereditary wealth, opportunistic investment, and some sweet latter-day deals that ensure him a great stream of income without working.  The issue isn’t just taxation, or whether private equity is good or bad.  The larger issue is that Romney’s life story belies the identity of interest between high and low that Republicans posits.  If the Romneys of the world are doing so well, why aren’t we?

Republicans argue that we should not restrain the wealthy or require them to give more to their country, because, through their activities as capitalists, they help us enough already.  If only we would let “free enterprise” alone, it would benefit us all in the natural course of things.  Yet Romney’s business career, the breadth of his opportunities, and his far-flung financial arrangements all exemplify the great divide between those enjoying the sweetest fruits of global capitalism and the masses of Americans contemplating the lowly uncertainties of the everyday.