Several readers have praised me for calling attention to the futility of appealing for “structural change” while presenting proposals that fail to address the “structural” problem. These same readers then chastised me for failing to present my own solutions to the problems I highlighted.

“Easy to call the kettle black,” they were, in effect, saying, “what do you propose that’s different?”

Fair enough. I’m not doing my job if I present only half an answer. To understand structural change is to understand two things: rules (be they formal laws, chosen policies or merely conventional wisdom) and changed circumstances that make the rules obsolete.

To effect structural change, we must first recognize the changed circumstances that make mere rule tinkering futile, and then we must formulate new “rules” that squarely address the changed circumstances.

Consider the example of the income tax. The problem is clear enough. We as a nation need to defend ourselves, provide for our public infrastructure, protect those in the shadows of life and pay our debts, all while encouraging entrepreneurs to create the products (and jobs) of the future.

Since 1913 at the federal level and since 1969 at the state level, we have taxed income.

This “rule” involves two steps — first, deciding what is income and, second, deciding how much of it government takes.

Much of today’s economic debate — from the Occupy movement, to calls for millionaires and billionaires to pay their “fair share,” to GOP presidential candidate Mitt Romney’s embarrassingly inarticulate efforts to disclose and explain his tax returns — has focused on the second part, that is, the rates different people pay.

Given today’s economic circumstances, this is largely a waste of time, fussing about deck chairs on the Titanic. The far, far greater structural instability and dysfunction lies in the definition of income.

Billionaires Warren Buffet and Romney pay effective tax rates that may be less than those of their secretaries not because the rates are unfair, but because their incomes derive from sources to which different rules apply. If there is any “unfairness” in the system, it lies in the rules defining income far more than in the rates of taxation.

The rates take up a page in the tax code. The rules defining income account for tens of thousands of pages and nearly as many court cases.

Claiming to address the need for “structural change” by calling for changes in income tax rates is akin to looking for lost car keys by the curb under the street lamp because the light is good, rather than in the bushes where you dropped them where it is dark. It may be easier, but it won’t get the car started.

The important circumstances we need to address with respect to taxation of income is the accumulation of special exemptions, credits, tax treatment and definitions that make the code both so complicated and so difficult to change.

Because each individual group — from the “holiest” non-profit to the most “obscenely” profitable oil speculator or Wall Street trader — has its own obscure but critical loophole that few others know or care about, it is extraordinarily easy to add changes to the tax code and extraordinarily difficult to remove them.

Yet remove them we must, if we are to make changes in our economy that are truly “structural.” We must somehow bring sufficient political will to the table to address the “structural” problem of defining income rather than cynically and divisively playing to political bases by tinkering with rates.

I believe that a great many people in the country actually recognize this fact and would support a serious “everything is on the table” approach to tax reform if someone had the political courage to propose it.

The essence of the proposal, however, would have to be that it did not take as its point of origin an appeal to the left-most or the right-most base of either party.

As difficult as it may be to define structural change, achieving it is a far greater challenge, one that can be accomplished only by the mandate of a large section of the center of our citizenry. But demonstrating the courage to undertake that challenging task is the only reason to support a politician today.

Charles Lawton is senior economist for Planning Decisions, a public policy research firm. He can be reached at:

clawton@maine.rr.com