The question arises: How effective are weasel words in fighting off weasel words?

With its leader having proposed to expand our deflating economy by redistributing another $1.5 trillion from private-sector producers to public-sector gluttons, the Obama Left’s talking point du jour is: “We are just asking the rich to pay their fair share.” The point here is not to rehearse the illogic of that assertion. The top earners in the economy already pay all of the income tax and virtually all of the taxes, period. You could look it up.

What I’d like to home in on is the single number the president and his diminishing ranks studiously ignore — the “x” in the equation that never quite gets a value assigned. “Fair share” — what is it?

Want to make a cable-news Democratic party-strategist squirm? Ask her what she means by the “fair share” that must be paid by the rich. (No point further tarrying over what she means by “the rich,” since we already know they are billionaires and millionaires who jump about in corporate jets while somehow making only $200,000 a year.) In response to the “fair share” question, you will hear how Bush single-handedly destroyed the economy. You will hear about the diabolical Republican plan to desert the elderly, starve the young, and exploit everyone in between. You will hear a vague concession that “the rich” must be allowed to keep some semblance of their wealth — enough, at least, to keep them in the game of “paying it forward” to future generations of government wards. But what you won’t hear is a number.

This week, I had the pleasure of watching the Fox Business Network’s Stuart Varney expertly press the Obama Left’s glib evaders on the subject. How much is a “fair share,” he doggedly inquired? A quarter? A third? Should the rich have to split their take 50-50 with Leviathan? Or is their success such a blight on social justice that the government (and the Teamsters, and the teachers’ unions, and the basket-case blue states) should get something much closer to all of it?

No answer. They cannot answer it.

The rise of the party-strategist class — driven by the imperative to fill yawning gaps in the 24/7 cable-news cycle — has contributed little to the coherence of our public-policy debate. It does, however, have its value: Its members will always show you what they most fear.

In this instance, they are deathly afraid of that number. The “fair share” can never be quantified — not in theory, not in practice. Conceptually, it is a non sequitur, because it gets the Left’s premise exactly backwards. To peg the rich man’s “fair share” at anything greater than zero would be to admit that the wealth is his in the first place. Having intensely focus-grouped the matter, the strategists are quite sure you’re not ready to be told that all wealth belongs to the state, and that since it is theirs, not yours, “fair share” is whatever they decide under the exigencies of the moment.

In practice, the strategists cannot quantify “fair share” because today’s exigencies are pretty exigent. There can never be an enough. The entitlement state that the Left has steadily erected for 80 years (with no small amount of help from Beltway Republicans) features a business model that, by comparison, makes Solyndra look like Apple.

Our accumulated debt, counting unfunded entitlement liabilities, now outnumbers by a goodly margin not only the total net worth of our entire country, but also the combined GDP of every country on earth. Consequently, the moment you put a real number on “fair share,” the game is over: The irredeemable failure of the entitlement state becomes as clear as two plus two, as does the urgency of defeating the most unabashed champion that entitlement state has ever had in the Oval Office. For a political strategist, getting your candidate defeated is not a good strategy.

Any good cross-examiner will tell you: Find the question the witness doesn’t want to answer, and, again and again, make him answer it — or, just as good, make him move heaven and earth to avoid answering it. Stuart Varney would have been a stellar trial lawyer if he hadn’t resolved to make a more honest living in finance.

But can you beat nothing with nothing? How effective are weasel words in fighting off weasel words?

In recent months, former Bush official Pete Wehner took issue with me for proposing that we end Medicare, a program in such dire straits that it will collapse of its own weight whether we end it or not. This week, the Manhattan Institute’s Nicole Gelinas vigorously objected to my defense of the proposition that Social Security is a Ponzi scheme. It is not my objective to rehearse the blow-by-blow of our exchanges. I admire both of them, and intramural debate is a singular asset of the Right, which encourages the diversity that actually matters: diversity of thought.

To boil it down to its essence, neither Pete nor Nicole took much issue with the legal, factual, or actuarial case I presented on these entitlement programs. Neither demurred from the contention that the programs are driving us over a cliff. Their principal point was that these programs are popular — woven, as Pete said of Medicare, into the fabric of America. To associate oneself with the position that Social Security was of dubious constitutionality, conceived in fraud, and ultimately unsustainable is, Nicole argued, to drive away the voters needed to oust the White House incumbent.

No one I know, least of all me, is arguing that we need to repeal compassion or common decency. I acknowledge thinking that the Republican intelligentsia’s apparent fondness for — or at least acceptance of — the entitlement state is redolent of the Left’s lack of faith in American individualism and our cultural inheritance. If Leviathan collapsed tomorrow, the states and the American people would instantly develop private and public welfare programs for the truly needy. They would spend billions on education, science, and technology, the only difference being that, with Americans making their own choices rather than allowing Big Government to usurp them, those dollars would chase real value rather than line the pockets of the regime’s union cronies and campaign bundlers.

But let us assume for argument’s sake that due deference for stability requires that we yield to the purported need for a federal welfare state. Why on earth should that require preserving the ruinous, duplicative, dysfunctional edifice that fills this role so miserably today? If what we really need is honest, transparent, means-tested welfare for those who truly cannot fend for themselves, why have we decided we are too incompetent to convince the country that we can have such a thing without failed and unsustainable programs such as Social Security and Medicare?

If Republicans are too craven for that fight, then GOP strategists be forewarned: You are headed for your own form of “fair share” squirming.

So, are you really content to claim that, with just a nip here and a tuck there, the federal government can and should direct a retirement program and a disability program and a Medicare program and the education system and medical research and the mortgage market and the creation of a green-energy sector and a global Islamic-democracy project and . . . and . . . and . . . ? If so, fine, but then you had better be ready to tell us how much it is going to cost and how we’re going to pay for it — including how much you’re going to raise taxes to pay for it — while paying the debt we’ve already run up, maintaining the unparalleled military might that makes prosperity possible, protecting the homeland from terrorist attacks, and running the DOJ, FBI, SEC, USDA, DOE, EPA, and on and on.

If the Left is going to be grilled on “fair share,” as it must be, we’d better be ready to counter with our own number. And we’d better be ready to explain how that number is going to cover the entitlement state we’re so earnestly promising to preserve.

—  Andrew C. McCarthy, a senior fellow at the National Review Institute, is the author, most recently, of The Grand Jihad: How Islam and the Left Sabotage America.