Forbes vs. Kinsley on the Flat Tax

Professor Caron over at TaxProf Blog provides an interesting post about Steve Forbes' new book, Flat Tax Revolution, and Michael Kinsley's critique thereof (which I have linked to directly here).

Mr. Kinsley's first argument against Mr. Forbes' plan (which calls for a 17% flat tax) is a good one.  When I was a student in Professor Kyle Logue's Income Tax I class, we learned about the tax code in three parts:

1: What is included in income?

2: What are the permitted deductions and credits?

3: Tax rates/calculating your tax

The appeal of a flat tax is to simplify part 3 (and, to a lesser extent, part 2), but as Mr. Kinsley puts it, "... progressive tax rates -- higher taxes on higher incomes -- aren't what make the current system so complicated. It's as easy -- even easier -- to multiply by 40 percent as it is to multiply by 17 percent...."  Rather, it's part 1 that's the real problem: "The complications come in defining and calculating income. Some of the complications are unavoidable, because people and companies have complicated affairs." 

Mr. Kinsley also attacks the (somewhat counterintuitive) idea that reducing taxes for everyone will actually increase tax revenues because lower taxes will "inspire" people to work harder.  I'll let Mr. Kinsley's words speak for themselves, since I find them delightfully catty:

... [L]et's note only that tax rates were higher than they are now when Steve Forbes had the inspiration to be born into a wealthy family, and higher still when his father, Malcolm, first built the family fortune.