If forced to pick, I might say the deduction for state and local taxes, which cost $67 billion in fiscal 2011, according to the congressional Joint Committee on Taxation. …

Taxpayers have been allowed to deduct state and local income and property taxes since the federal income tax began in 1913. (Sales taxes have at times been deductible, too, but that’ s a relatively minor issue.) The theory is it’s unfair to make people pay twice for the public services they receive. That’s doubtful, though, since, despite some overlap, federal taxes support different services than state and local. …

Two states, California and New York, reaped almost 30 percent of the deduction’s value in 2009, the latest year for which I could find Internal Revenue Service data. Other states that benefit disproportionately include Connecticut, New Jersey, Illinois, Massachusetts and Maryland. …

Starting to notice a pattern? Basically, what we have is a significant federal tax subsidy for “blue” state governments. These also happen to be the states having the most difficulty living within their means, what with their expensive urban school systems, bloated pension liabilities and all. Yet they have an incentive to close their budget gaps by raising income taxes rather than reining in spending, because the deduction helps them pass the tab to other states, most of them red.