Mitt's impossible math...

Ezra Klein at WaPo:

I can describe Mitt Romney’s tax policy promises in two words: mathematically impossible.

Those aren’t my words. They’re the words of the nonpartisan Tax Policy Center, which has conducted the most comprehensive analysis to date of Romney’s tax plan and which bent over backward to make his promises add up. They’re perhaps the two most important words that have been written during this U.S. presidential election.

If you were to distill the presumptive Republican nominee’s campaign to a few sentences, you could hardly do better than this statement of purpose from the speech Romney delivered in Detroit, outlining his plan for the economy: “I believe the American people are ready for real leadership. I believe they deserve a bold, conservative plan for reform and economic growth. Unlike President Obama, I actually have one — and I’m not afraid to put it on the table.”

The truth is that Romney is afraid to put his plan on the table. He has promised to reduce the deficit, but refused to identify the spending he would cut. He has promised to reform the tax code, but refused to identify the deductions and loopholes he would eliminate. The only thing he has put on the table is dessert: a promise to cut marginal tax rates by 20 percent across the board and to do so without raising the deficit or reducing the taxes paid by the top 1 percent.

The Tax Policy Center took Romney at his word. They also did what he hasn’t done: They put his plan on the table.

To help Romney, the center did so under the most favorable conditions, which also happen to be wildly unrealistic. The analysts assumed that any cuts to deductions or loopholes would begin with top earners, and that no one earning less than $200,000 would have their deductions reduced until all those earning more than $200,000 had lost all of their deductions and tax preferences first. They assumed, as Romney has promised, that the reforms would spare the portions of the tax code that privilege saving and investment. They even ran a simulation in which they used a model developed, in part, by Greg Mankiw, one of Romney’s economic advisers, that posits “implausibly large growth effects” from tax cuts.

The numbers never worked out. No matter how hard the Tax Policy Center labored to make Romney’s promises add up, every simulation ended the same way: with a tax increase on the middle class. The tax cuts Romney is offering to the rich are simply larger than the size of the (non-investment) deductions and loopholes that exist for the rich. That’s why it’s “mathematically impossible” for Romney’s plan to produce anything but a tax increase on the middle class...