• The charity loophole. For billionaires like Mr. Buffett, the single most important deduction in the tax code is for charitable giving. Middle-class earners can’t give nearly as much money away to reduce their overall tax burden. Yet we don’t hear Mr. Buffett calling for the elimination of that deduction in the name of fairness.

Mr. Buffett has also already sheltered the bulk of his fortune from federal taxes by putting them into a foundation that will give the money away. That’s an act of generosity, but if the government’s purposes are so vital, why doesn’t he simply give the money to the IRS?

Rebecca Quick of CNBC put that question to Mr. Buffett in 2007. His answer: “Well, that’s a choice and it’s an option . . . If I had to give it to a single individual, or make some young Buffett a multibillionaire, or give it to the government, I’d absolutely give it to the government. I think that on balance the Gates Foundation, my daughter’s foundation, my two sons’ foundations will do a better job with lower administrative costs and better selection of beneficiaries than the government.”