Josh Barro had a very nice discussion of the issues involved in simplifying the income tax code, as proposed by most of the Republican presidential candidates. He concludes with a discussion of what would probably the greatest simplification for most taxpayers: have the I.R.S. prepare returns that could be corrected by taxpayers if they thought there was an error.

This is now done in some European countries, such as Denmark and Spain. As Barro explains, it could also be done here, for people who file the standard deduction, which is most taxpayers. Barro points out that the number using the standard deduction could be increased by eliminating some deductions. This is true, but it would also be possible to increase the number of people taking the standard deduction by increasing its size.

Unfortunately, because of the power of H&R Block, few politicians are likely to propose this simplification that would be an enormous benefit to tens of millions of taxpayers. As Barro points out, none of the Republican simplifiers have it on their agenda.