David Frum asks a good question

Specifically, Frum says the following:

"Here's what I don't get.

"Mitt Romney claims that his new proposal to reduce the top rate of federal personal income tax to 28% will not benefit the top 1%.

"I’m going to limit the deductions and exemptions particularly for the higher-income folks. For high-income folks, we’re going to cut back on that, so that we ensure that the top 1 percent keeps paying the current share they’re paying and more.

"How does the math on this remotely work?

"Yes, I can imagine that a scale-back in the deductions for state and local taxes or mortgage interest might conceivably balance the value of the tax cut for a family at the lower edge of the top 1%. But what possible change in the deduction schedule could offset the value of a 7 point tax cut for somebody earning more than $1 million, much less more than $10 million?"

There are two possible answers to this. The first, which I had in mind when I wrote my blog posts (such as here) on the Romney tax plan, and which is consistent with what Romney said above, is that everyone gets tax cuts, hence the rich can pay much less than under current law and still match their "current share" (i.e., their percentage of overall annual income tax liability). Note that, while in this scenario they would be paying the same percentage of overall income tax revenues as previously, they would get much larger tax cuts than anyone else as measured in dollar terms, and would also probably get greater percentage increases in after-tax income. But the Romney camp has carefully picked the measure of progressivity that puts the best distributional face on his plan.

The second answer, which I suspect is true as well, is that the Romney claims are at best misleading. For example, did they use representative individuals on the lower end of the top 1% to make their point? But even if their claim is true for the top 1% as a whole, it's just undoubtedly the case (as Frum suggests) that people in the upper reaches of the top 1% end up paying a smaller tax share than they do today, under any possible measure.